Related
I think I may have a simple yet very inefficient method of ensuring stable overclock at higher frequencies. I have been messing around with many different OC kernels (along with many different roms ), and have noticed the same situation. While charging, all overclock speeds beyond 633 are pretty stable. It may take a few attempts to reach a certain speed (as the phone might reboot), but once successful its all golden!
I'd previously though instabilities were due to the fact that these kernels were undervolted and thus, after a certain frequency, needed more juice to function properly, but when I removed the charger. My god...it still ran! Just as effectively for extended periods of time.
The only problem was the phone would either reboot or hang if the screen was powered-off and idle/sleep for more than 1-3 secs. So I tried using SetCpu's profiles to lower the clock speed to various speeds below 633 during sleep. Yet to no avail. The phone would always freeze/reboot when it attempted to clock back up.
So if someone were to develop an app that would implement a toggle feature, or make modifications to the current kernels to disable sleep for test purposes I believe that might help. I am far too inexperienced a programmer to dev this but know there was a command under reference called "Partial Wake Lock" that can disable cpu sleep.
Also I realize, if implemented as is, this will destroy battery life. But with a good toggle switch it can be treated as an Overdrive mode!!!
Forgot to mention that while charging and clocked beyond 633 it always awoke with no problems.
My phone will clock to 710 before freezing up but it's crazy unstable. It seems to behave well at 652 with a freeze up roughly every 6-7 hours. I've never tried it that high with the charger though. Seems interesting.
extended batteries also reduce overclocking, my 2600mah battery peaks at 595, where as the official battery gets me to 633
-------------------------------------
Sent from my HTC Magic
I have exactly the same issue. My G1 runs stable on 672, while plugged in into
the charger. Even using GPS for navigation, browsing and so on, everything works great. As soon as the charger is plugged out and the phone goes into sleep it reboots.
I end up in changing the frequencies on demand with setCPU. When i need more speed, e.g. browsing the web, i set it manually to 672. And before putting it in my pocket i reduce to 614. Even on battery i can use 672.
Also tried profiles in SetCPU but this did not help.
BTW. Using 5.0.8t4, same was on t3
Damian
Nagoki said:
I think I may have a simple yet very inefficient method of ensuring stable overclock at higher frequencies. I have been messing around with many different OC kernels (along with many different roms ), and have noticed the same situation. While charging, all overclock speeds beyond 633 are pretty stable. It may take a few attempts to reach a certain speed (as the phone might reboot), but once successful its all golden!
I'd previously though instabilities were due to the fact that these kernels were undervolted and thus, after a certain frequency, needed more juice to function properly, but when I removed the charger. My god...it still ran! Just as effectively for extended periods of time.
The only problem was the phone would either reboot or hang if the screen was powered-off and idle/sleep for more than 1-3 secs. So I tried using SetCpu's profiles to lower the clock speed to various speeds below 633 during sleep. Yet to no avail. The phone would always freeze/reboot when it attempted to clock back up.
So if someone were to develop an app that would implement a toggle feature, or make modifications to the current kernels to disable sleep for test purposes I believe that might help. I am far too inexperienced a programmer to dev this but know there was a command under reference called "Partial Wake Lock" that can disable cpu sleep.
Also I realize, if implemented as is, this will destroy battery life. But with a good toggle switch it can be treated as an Overdrive mode!!!
Click to expand...
Click to collapse
The speeds will be different on different phones due to the hardware even slightly different depending on where the phone was made mine can go to 720mhz while others 614mhz which means unless another way of overclocking is found then we won't have a stable overclock for a while :/
mejorguille said:
My phone will clock to 710 before freezing up but it's crazy unstable. It seems to behave well at 652 with a freeze up roughly every 6-7 hours. I've never tried it that high with the charger though. Seems interesting.
Click to expand...
Click to collapse
Lemme know how that goes. I've noticed higher clock frequencies are much more stable while charging.
Jedipottsy said:
extended batteries also reduce overclocking, my 2600mah battery peaks at 595, where as the official battery gets me to 633
-------------------------------------
Sent from my HTC Magic
Click to expand...
Click to collapse
That's strange. Maybe its a voltage difference between batteries that makes its more unstable.
vassloff said:
I have exactly the same issue. My G1 runs stable on 672, while plugged in into
the charger. Even using GPS for navigation, browsing and so on, everything works great. As soon as the charger is plugged out and the phone goes into sleep it reboots.
I end up in changing the frequencies on demand with setCPU. When i need more speed, e.g. browsing the web, i set it manually to 672. And before putting it in my pocket i reduce to 614. Even on battery i can use 672.
Also tried profiles in SetCPU but this did not help.
BTW. Using 5.0.8t4, same was on t3
Damian
Click to expand...
Click to collapse
I believe when the phone is charging the operating system either suspends or extends idle/sleep when the screen backlight is off. This would explain why it reboots on battery and not while plugged in. Also the SetCpu profiles would work if only overclocking wasn't so unstable.
xillius200 said:
The speeds will be different on different phones due to the hardware even slightly different depending on where the phone was made mine can go to 720mhz while others 614mhz which means unless another way of overclocking is found then we won't have a stable overclock for a while :/
Click to expand...
Click to collapse
That is true, but if we can help the relative stability of each clock rate past 528 by using simple methods (i.e. overclocking while charging), we can simply aim to improve its reliability until a better way to overclock is found.
Wanted to share my recent experience about efficient combinations of ROMs, kernels, radios. It appears there is a consensus that the combinations you chose is a matter of taste, and all reasonable/compatible ROM - Kernel - radio combos work well. That is not what happened to me. I was moving from BAFM 1.7, imo's lean kernel to BAFM 1.8.6 to get the MR2 radio (and get rid of excessive 4G battery burn bug). Before the move the phone would lose 2% battery overnight -- pretty good in my book. I was surprised that after flashing 1.8.6 I could not get nowhere near that level of efficiency. After unsuccessfully trying a number of combinations, the one that consistently got me back to 2% loss overnight was Adrynalyne's kernel (the one that comes with the ROM) and leaked MR2 radio. Adding either Imo's lean kernel, MR2 OTA radio or both screwed things up, and I could not keep the phone from using less than 1% of battery per hour on idle no matter how much I tried. To me that was a surprise (with the kernel at times it worked well, but then it would start using 10% of CPU constantly without any apps running and I could not stop that save for a reboot).
Needless to say, I was in a testing mode so I wiped each time before re-flashing the ROM, and even limited app installs to a bare minimum to keep things clean, monitored app CPU usage, etc.
SO, maybe there is value to asking about efficient ROM / Kernel / Radio combos that work well! I thought I could just use BAFM 1.8.6, imo's kernel, OTA MR2 radio, but somehow that was a screwy combination, and it took me a week to get things right.
I agree that the combo of ROM/Kernel/Radio does matter a great deal on battery life.
You also have to think, each and every phone is different, so a combo that works for one person, might not be as good for another. This is why when people ask what the best combo is, a lot of people say its what ever works best for you, which is very true.
I have random problems with wifi - does not connect when wifi is in range. Just block the tiwilan_wq and *wakelock*. I suppose that is voltage problem.
How to see and change the wifi voltage without changing the kernel.
sripts, zips and terminal commands are welcome.
10x
think that's a different issue, not sure though, I usually restart the phone when that happens, also imma try to change it tomorrow
i know that. but with some ROM/Kernel combinations is much less. Moreover the solution with WIFI always on is not a solution. I would like to experiment with different voltages. As this problem concern only few device form different mark i suppose that is hardware issue. in my live as computer overclocker i know that 10-20% more voltage do not hurt much but save many troubles caused by bad lot-to-lot difference
Strongly not recommended, go too far off and you end up with no wifi at all.
Anyway, the files you're looking for are in /system/etc/wifi/tiwlan.ini (location of this file may vary).
I will not be responsible if you destroy your wifi chip (or worse) if you input wrong values.
I know where is the file. But I do not see the values about voltage. I know that in many coocked ROMs the values are heavenly decreased for fight with battery drain and i do not know how much is in my now.
Sent from my LG-P920 using xda app-developers app
Near the bottom of the file under Radio parameters for TQS_S_2.6 and Radio parameters for RFMD_S_3.5. I looked at this from the v21E stock rom.
Okay, I'm officially sick of battery drain. My first time with this issue was after flashing CM10, my GB build before that gave me the perfect amount of battery life. My phone would last throughout the day on GB. I got sick of the drain on CM10 after a week and flashed GB back to my device. My battery life has been normal the past few months on GB.
Since the official ICS builds were released I've been using ICS. I first flashed V28, battery drain was just like CM10. I flashed GB back and battery went back to normal. The next day official AT&T V30B was released, so I flashed it. Battery drain came back again.
Every single rom above GB has caused battery drain for my device. I've tried every suggested method I could find online. Flashing a different kernel, setting CPU Governor to hotplug, using nstools. I've done everything. I keep my phone in airplane mode, auto-sync is turned off, my brightness is at the lowest setting, gps and location settings are set to off, bluetooth is also off. I've tried charging the battery fully, pulling the battery out for a minute, charging fully again, pulling it again, charge some more, that didn't help at all.
My battery is dropping 10% in 15 minutes and all I have open is the web browser. This never happens on GB, no matter when I flash it. I don't understand what the issue is. I've also fully wiped my device internally and externally. I've spent a couple of hours trying to find an answer but nothing helps. If you can assist me, please take a minute and do so, this is frustrating. Thanks in advance.
Well generally yes. ICS+ drains a lot more battery than GB for a reason. Its running many more system apps and this can put a strain on battery life with the system working that hard "While Sleeping too". If you really cant take the drain.. Order and extended battery online. I suggest checking out the Accessory section. Good luck!
Sent from my R800i using xda app-developers app
Greenify + betterbatterystats
Two great apps that will help with battery life
Am i the only one getting significantly BETTER battery life on ICS?
mchartier said:
Am i the only one getting significantly BETTER battery life on ICS?
Click to expand...
Click to collapse
No. You are not. ICS consume much less battery due to the better RAM organization and memory killer. Just in many ROMs there is too much stupid programs and in many KERNELs are not optimized. Moreover people compare all data switched off of GB and the many process running by default in ICS that they can switch off.
The ROM/Kernel combination (by Acura) in my signature give me 48h battery life - the same like the GBs by Acura or Darkroom Team.
So... it is better not to compare STOCK GB with STOCK ICS - you never know the tweaks and running stuff by default. Better compare Developer GB with the SAME developer ICS ROM if you want to claim such a think.
AW: Android Experts Only - Battery Drain
mchartier said:
Am i the only one getting significantly BETTER battery life on ICS?
Click to expand...
Click to collapse
No, mine is better, too.
Sent from my LG-P920 using xda app-developers app
mchartier said:
Am i the only one getting significantly BETTER battery life on ICS?
Click to expand...
Click to collapse
Me too, at least comparing the stock GB with the stock ICS.
There's no use of comparing custom ROMs/kernels anyway.
botson71 said:
Me too, at least comparing the stock GB with the stock ICS.
There's no use of comparing custom ROMs/kernels anyway.
Click to expand...
Click to collapse
nope. other way around. you never know what kind of sh*t is on is in STOCK, and you know that custom (developers) ROM are clean form most of them and tweaked for performance and battery. Stock mean ... "tweaked" and filled with bloatware by LG - nothing more.
p-vlad said:
nope. other way around. you never know what kind of sh*t is on is in STOCK, and you know that custom (developers) ROM are clean form most of them and tweaked for performance and battery. Stock mean ... "tweaked" and filled with bloatware by LG - nothing more.
Click to expand...
Click to collapse
True about the custom roms but you missed my point about the stock roms.
When someone claims for example that "the new xxx rom for my phone is worse/better than the old yyy rom", you have to ask "under what conditions". And in order to make a reasonable and reliable comparison, you need to compare the old and new stock roms and run the battery benchmarks only on those.
This is exactly what the biggest tech sites and magazines do when comparing the batteries. They run the tests on STOCK conditions/roms with as few apps as possible, apart of the stock apps.
Battery comparison is a delicate business. For example, even if you have the same two phones with the same stock roms, if the one phone receives a weaker 2G/3G or WiFi signal, its battery will finish much faster than the other one.
And if you start adding apps, changing to custom roms, kernels, radios and bootloaders then you have far too many factors in order to make a reliable comparison.
Okay, I tried geenify and bbs on a full charge and experienced no changes. My battery is dying quickly as we speak. My battery went from 81% to 34% in 5 1/2 hours in idle. I don't see how I'm having this issue and everyone else isn't.
botson71 said:
True about the custom roms but you missed my point about the stock roms.
When someone claims for example that "the new xxx rom for my phone is worse/better than the old yyy rom", you have to ask "under what conditions". And in order to make a reasonable and reliable comparison, you need to compare the old and new stock roms and run the battery benchmarks only on those.
This is exactly what the biggest tech sites and magazines do when comparing the batteries. They run the tests on STOCK conditions/roms with as few apps as possible, apart of the stock apps.
Battery comparison is a delicate business. For example, even if you have the same two phones with the same stock roms, if the one phone receives a weaker 2G/3G or WiFi signal, its battery will finish much faster than the other one.
And if you start adding apps, changing to custom roms, kernels, radios and bootloaders then you have far too many factors in order to make a reliable comparison.
Click to expand...
Click to collapse
"biggest tech sites and magazines" do PAID "comparisons" from A to Z. Do not trust any of them. Better compare best of X with best of Y. Or worse of X with the worse of Y. Like a scientist and like computer overclocker I know what means "Average" values.... there is no such a think. As i said - stock is just made by somebody... that is all... and here the developers are better. Moreover you do not know the current person how install the "Stock" Rom. If he did reset, if he still is on ext3 or on ext4. Does the person did a hard reset or not. Does still keep old baseband by installing the simple BIN or the BIN with baseband or the KDZ (bin+bb). different basebands different signal power etc etc etc... thats why i said BG of X with the ICS of X developer - they use nearly the same tweaks in all Roms with additions.
I had battery drain problem on all roms since GB untill v28b.
I lose about 1-2% during the night with wifi always on..I mean really always ON.[Thats 2% during 8h of sleep, on darkroom v2 i had 35% loss]
During the day my battery can last around 12h-15h..
My other,extended battery 3500mAh makes things a lot easier for gaming. I recharge them during the night and woooo..
V28b is the best rom and you should try flashing kdz with Mobile support tool like this:
http://p92x.acidhazardrom.com/guides/lg_flash_tool.html
There have been problems while flashing bin and fls but you never know, it's different for any user.
The second thing you should do is to erase or freeze any system app that you don't use.
For example I erased adrenalin6,gtalk,lg apps,........... and left only the apps that I really need.
I'm on stock v28b with the stock kernel and I have no problems.
And buy a new battery, maybe that's the problem..They are cheeeeep.
me to i have a very good lif batterie after flashe 28b i sharge it 100% wifi 3or 4 h day blut 1h day ande calls lyck always
for 1 day in GB v21e at 19:00 may batteri is in 20 or 15% CHARGE
in v28b for 1 day at 19:00 may batteri is in 55 or 50% CHARGE
send from my LG p920 ics v28b
Android1993 said:
Okay, I tried geenify and bbs on a full charge and experienced no changes. My battery is dying quickly as we speak. My battery went from 81% to 34% in 5 1/2 hours in idle. I don't see how I'm having this issue and everyone else isn't.
Click to expand...
Click to collapse
That is too much loss IF what you say is correct that your phone is idle..
My O3D with wifi on and ICS during nighttime goes from 100% to 95% and btw my battery is the original that i bought with the phone back in the summer of 2011.
It doesnt run on stock ROM but it does run on stock kernel for now...
And btw guys forget about magazine tests and such BS because they are just promoters...
Never compare STOCK ROMS with CUSTOM ROMS because custom ROMS will always be better than STOCK, thats the way its meant to be.
xbsall said:
That is too much loss IF what you say is correct that your phone is idle..
My O3D with wifi on and ICS during nighttime goes from 100% to 95% and btw my battery is the original that i bought with the phone back in the summer of 2011.
It doesnt run on stock ROM but it does run on stock kernel for now...
And btw guys forget about magazine tests and such BS because they are just promoters...
Never compare STOCK ROMS with CUSTOM ROMS because custom ROMS will always be better than STOCK, thats the way its meant to be.
Click to expand...
Click to collapse
I reverted back to GB, factory reset, now I'm flashing V30B one last time, I'll do a factory reset upon starting it up. Let's see if whatever has been broken the last 3 times gets fixed.
UPDATE: I think I got down to the issue. The phone isn't correctly reading the battery. I did a shut down and reboot and it went from 93% to 86% , I then plugged it in, shut it down and reboot again and it read 100%.
I'm done. I'll probably stick with GB til I get a new device.
p-vlad said:
"biggest tech sites and magazines" do PAID "comparisons" from A to Z. Do not trust any of them. Better compare best of X with best of Y. Or worse of X with the worse of Y. Like a scientist and like computer overclocker I know what means "Average" values.... there is no such a think. As i said - stock is just made by somebody... that is all... and here the developers are better. Moreover you do not know the current person how install the "Stock" Rom. If he did reset, if he still is on ext3 or on ext4. Does the person did a hard reset or not. Does still keep old baseband by installing the simple BIN or the BIN with baseband or the KDZ (bin+bb). different basebands different signal power etc etc etc... thats why i said BG of X with the ICS of X developer - they use nearly the same tweaks in all Roms with additions.
Click to expand...
Click to collapse
You missed my point again.
Of course the good tweaked custom roms/kernels etc are far better than any stock roms, and not only in battery life, there's absolutely no question about that.
But when someone claims "the ICS rom has better/worse battery than the GB rom" it's much easier and more reliable to compare the ICS/GB stock roms than the custom roms, because of the much fewer degrees of freedom.
In a nutshell:
-Comparing, e.g., GB 21E stock rom with the ICS 28B stock rom: easy.
-Comparing, e.g., GB 21E custom rom which has different tweaks/kernels etc with an ICS custom rom which has again different tweaks/kernels etc: not so easy.
I'm having the same battery drain problem with mine too. Its driving me crazy to have to charge my phone 2-3 times a day
Sent from my LG-P925 using xda app-developers app
botson71 said:
You missed my point again.
Of course the good tweaked custom roms/kernels etc are far better than any stock roms, and not only in battery life, there's absolutely no question about that.
But when someone claims "the ICS rom has better/worse battery than the GB rom" it's much easier and more reliable to compare the ICS/GB stock roms than the custom roms, because of the much fewer degrees of freedom.
In a nutshell:
-Comparing, e.g., GB 21E stock rom with the ICS 28B stock rom: easy.
-Comparing, e.g., GB 21E custom rom which has different tweaks/kernels etc with an ICS custom rom which has again different tweaks/kernels etc: not so easy.
Click to expand...
Click to collapse
i got your point but....
lets hypothetically say:
1. Stock ROM GB give 75% of the max possible (best score of LG developers for 2 years developing from v. 10A to 21E). Stock ROM ICS 50% of the max possible (best score of LG developers for first leaked ROM)
2. Custom ROM GB - 99-99-99% of the max possible (best for developers A1, A2, A3). Custom ROM ICS 96-98-99% of the max possible (best for developers A1, A2, A3)
so...witch you think is better to compare - 50 with 75 from the max possible ("max possible" is the key phrase for speed, battery etc.) for LG
or comparing 98 with 99 for each GB or ICS custom... i would compare the last one. if 98 for GB is 16h and 99 for ICS is 14h ... then OK. GB is better. but not by original LG roms.
that is my point.
And another O3D tale...without happy end ;(
1.) Stock GB under heavy use (more then 3 hours of SMS, games & WiFi over the day) = A battery life of 13-19 hours
2.) Stock ICS v30a under minimal use (some SMS, little gaming and WiFi) = A battery life of approx. 10 hours
3.) Stock ICS v30a + ROOT, nearly no use at all over the day, no WiFi, (just 3 SMS) = A battery life of 7 hours.
After 2 hours in my jeans pocket = 68% of battery left
After 7 hours in ma jeans pocket = 8% of battery left (just 3 SMS written)
Then I read "Battery Re-Calibration" is of no use...and did not try it.
Then I read TaskKillers are nearly useless and un-installed "Advanced Task Killer"...didnt help. Re-Installing it didnt help either.
What is goin on here ?
May I suggest to check the CPU VRM (voltage regulator module) setting? I found out why, undervolting the CPU solved my problem. Voltage = ampere due to either linear and/or switchmode voltage regulator design.
EDIT: To clarify why voltage = ampere equations is true; ever wonder why PC motherboard gets away with shoving 100 Amps of power into the CPU without melting the 12V plug? In nutshell, battery trades amperage consumption for voltage shunted by inductor in switchmode VRM - in other word, battery have to work harder on higher CPU voltage settings but takes it easier at idle voltage.
Sent from my LG-P920 using XDA
You may have heard about how flashing a new ROM can improve your Android experience, but flashing a new kernel is one of the best ways to improve your phone's performance, battery life, and even add some saucy new features. Whether you know anything about either, here's what you need to know to make it happen.
What Is a Kernel?
A kernel in an operating system—in this case Android—is the component responsible for helping your applications communicate with your hardware. It manages the system resources, communicates with external devices when needed, and so on. Android uses a variation of the Linux kernel. A kernel is not the same as a ROM, even though you install them in mostly the same way. A ROM is a bit more all-encompassing. It's the operating system you use on your phone, the software your phone uses to get things done—the kernel is the bridge between that ROM and your hardware. All ROMs come with a kernel installed, but you can install a third-party one if you like—and that's what this post is about.
What a New Kernel Can Do For Your Phone
Flashing kernels isn't quite as talked about as flashing ROMs, but it can do a ton for your phone, namely in the way of battery life and performance—though it can also add extra features to your device, too. Here are some things to look for when choosing a new kernel.
Better Performance and Battery Life
This is the big change a new kernel can bring to your device. I'd separate these into two categories, but they're so intertwined that you really need to consider both when picking a kernel. There are a bunch of different kernel features that contribute to this:
Clock Speeds: In a very basic sense, higher clock speeds will improve performance on your phone. Flashing a new kernel allows you to overclock your phone, using higher clock speeds than the manufacturer intended. They can also let you reach lower clock speeds, so you can underclock your phone when you aren't using it, thus saving battery life. Your kernel will only give you the option to do so, however; if you want to overclock, you'll have to flash the kernel in question and then use something like SetCPU or CPU Tuner to tweak the clock speed.
Voltage: Higher clock speeds use up more battery on your phone because they require more voltage. However, some ROMs come with lower voltage limits, which means your phone will run just as fast, but use up less battery. Some will even overclock and undervolt your phone, though all of this comes at the expense of stability—if you notice that your phone goes into a boot loop, or reboots at random times, you'll want to either lower your clock speed or upgrade to a kernel with a higher voltage. Some ROMS have further sub-categories in this section, like Hybrid Adaptive Voltage Scaling (HAVS), which can be better for battery life (at the risk of stability) and Static Voltage Scaling (SVS), which keeps your phone at a steady voltage.
CPU Governors: Different kernels can support different CPU Governers, which manage the way your phone ramps up or down its clock speeds as you use it. There are a few different kinds you'll see, including Conservative, which focuses on battery life by ramping up your CPU very gradually when needed; Interactive, which focuses more on performance and smoothness by scaling up the CPU faster; InteractiveX, which is like Interactive but scales the CPU down when your screen is off (for better battery life); and Smartass, which is similar to Conservative but takes more factors into account when ramping up the CPU.
Task Scheduler: Kernels come with two different types of task schedulers: the Completely Fair Scheduler (CFS) and the Brain F**k Scheduler (BFS). CFS kernels are designed for regular phone use, like texting, web browsing, and otherwise multitasking apps on your phone. Most stock kernels are CFS kernels. BFS kernels focus more on whatever app is in the foreground, which is great for things like games but can be a bit laggier and a bit less stable.
These are the biggest features, but kernel developers add in all kinds of other tweaks to their kernels when possible, whether its introducing a more efficient file system, making the RAM more efficient, and so on. Again, they should list the tweaks in their description, so read up on the kernels for your specific device to learn more. I'd also recommend checking out XDA user mroneeyedboh's HTC Evo 4G kernel starter guide, from which much of this information comes.
Extra Features
Kernels can also add full features to your phone, or fix other issues that the manufacturer hasn't attended to yet. For example, while a lot of phones support Wi-Fi tethering out of the box, some—like the Motorola Droid—don't. If you find your phone isn't letting you tether using apps like Wi-Fi Tether, you might need to flash a new kernel that supports Wi-Fi tethering on your device. Kernels for Samsung phones can add support for a feature called Backlight Notification (BLN), which, coupled with an app, can turn your phone's buttons into notification lights.
Keep an eye out for features you don't want, too. For example, some HTC kernels come with a feature called Superior Battery Charging, or SBC, that can overcharge your battery for better life—but is likely to shorten your battery's life at best, or make it unstable at worst. I'd avoid kernels with this feature. You should also watch out for kernels that disable certain features of your phone—since some features are manufacturer-specific, you won't be able to get them in other ROMs or kernels. A good example of this is HDMI support on the EVO 4G.
Again, just make sure you research all the kernels available for your device, and know what you're getting yourself into before you flash. Most phones should have a large forum thread somewhere on XDA or RootzWiki that lists all the kernels available for their device. Make sure you choose a compatible one, too—the version of Android you're running determines what kernels you can use, so make sure you don't flash a Sense kernel on an AOSP ROM (like CyanogenMod), and make sure you don't flash a Froyo kernel on a Gingerbread phone—they won't play nicely together.
How to Flash a New Kernel
Once you've found a kernel you want to flash, download it to your device. It should be in ZIP format. Flashing a kernel is almost exactly like flashing a new ROM. You'll need to flash a new recovery to your phone, like ClockworkMod, which you can flash with ROM Manager. Put the ZIP file on your phone's SD card, then start up ROM Manager and go to "Install ROM from SD Card". Choose the kernel's ZIP file and continue. Note, however, that some kernels require that you flash them through your recovery mode instead of with ROM Manager—so once again, do your due diligence on its home page before you go a-flashin'.
The main difference between flashing a ROM and flashing a kernel is that you do not want to wipe your data. Wipe the Dalvik Cache only, and back up your ROM if desired (I highly recommend doing so, in case something goes wrong). Other than that, you should be golden. If you haven't flashed a ROM before, I recommend reading up on that first—but if you're familiar with that process, flashing a kernel shouldn't be a big shock to the system.
SOURCE - - - Lifehacker.com
Started from the bottom
Tha TechnoCrat said:
You may have heard about how flashing a new ROM can improve your Android experience, but flashing a new kernel is one of the best ways to improve your phone's performance, battery life, and even add some saucy new features. Whether you know anything about either, here's what you need to know to make it happen.
What Is a Kernel?
A kernel in an operating system—in this case Android—is the component responsible for helping your applications communicate with your hardware. It manages the system resources, communicates with external devices when needed, and so on. Android uses a variation of the Linux kernel. A kernel is not the same as a ROM, even though you install them in mostly the same way. A ROM is a bit more all-encompassing. It's the operating system you use on your phone, the software your phone uses to get things done—the kernel is the bridge between that ROM and your hardware. All ROMs come with a kernel installed, but you can install a third-party one if you like—and that's what this post is about.
What a New Kernel Can Do For Your Phone
Flashing kernels isn't quite as talked about as flashing ROMs, but it can do a ton for your phone, namely in the way of battery life and performance—though it can also add extra features to your device, too. Here are some things to look for when choosing a new kernel.
Better Performance and Battery Life
This is the big change a new kernel can bring to your device. I'd separate these into two categories, but they're so intertwined that you really need to consider both when picking a kernel. There are a bunch of different kernel features that contribute to this:
Clock Speeds: In a very basic sense, higher clock speeds will improve performance on your phone. Flashing a new kernel allows you to overclock your phone, using higher clock speeds than the manufacturer intended. They can also let you reach lower clock speeds, so you can underclock your phone when you aren't using it, thus saving battery life. Your kernel will only give you the option to do so, however; if you want to overclock, you'll have to flash the kernel in question and then use something like SetCPU or CPU Tuner to tweak the clock speed.
Voltage: Higher clock speeds use up more battery on your phone because they require more voltage. However, some ROMs come with lower voltage limits, which means your phone will run just as fast, but use up less battery. Some will even overclock and undervolt your phone, though all of this comes at the expense of stability—if you notice that your phone goes into a boot loop, or reboots at random times, you'll want to either lower your clock speed or upgrade to a kernel with a higher voltage. Some ROMS have further sub-categories in this section, like Hybrid Adaptive Voltage Scaling (HAVS), which can be better for battery life (at the risk of stability) and Static Voltage Scaling (SVS), which keeps your phone at a steady voltage.
CPU Governors: Different kernels can support different CPU Governers, which manage the way your phone ramps up or down its clock speeds as you use it. There are a few different kinds you'll see, including Conservative, which focuses on battery life by ramping up your CPU very gradually when needed; Interactive, which focuses more on performance and smoothness by scaling up the CPU faster; InteractiveX, which is like Interactive but scales the CPU down when your screen is off (for better battery life); and Smartass, which is similar to Conservative but takes more factors into account when ramping up the CPU.
Task Scheduler: Kernels come with two different types of task schedulers: the Completely Fair Scheduler (CFS) and the Brain F**k Scheduler (BFS). CFS kernels are designed for regular phone use, like texting, web browsing, and otherwise multitasking apps on your phone. Most stock kernels are CFS kernels. BFS kernels focus more on whatever app is in the foreground, which is great for things like games but can be a bit laggier and a bit less stable.
These are the biggest features, but kernel developers add in all kinds of other tweaks to their kernels when possible, whether its introducing a more efficient file system, making the RAM more efficient, and so on. Again, they should list the tweaks in their description, so read up on the kernels for your specific device to learn more. I'd also recommend checking out XDA user mroneeyedboh's HTC Evo 4G kernel starter guide, from which much of this information comes.
Extra Features
Kernels can also add full features to your phone, or fix other issues that the manufacturer hasn't attended to yet. For example, while a lot of phones support Wi-Fi tethering out of the box, some—like the Motorola Droid—don't. If you find your phone isn't letting you tether using apps like Wi-Fi Tether, you might need to flash a new kernel that supports Wi-Fi tethering on your device. Kernels for Samsung phones can add support for a feature called Backlight Notification (BLN), which, coupled with an app, can turn your phone's buttons into notification lights.
Keep an eye out for features you don't want, too. For example, some HTC kernels come with a feature called Superior Battery Charging, or SBC, that can overcharge your battery for better life—but is likely to shorten your battery's life at best, or make it unstable at worst. I'd avoid kernels with this feature. You should also watch out for kernels that disable certain features of your phone—since some features are manufacturer-specific, you won't be able to get them in other ROMs or kernels. A good example of this is HDMI support on the EVO 4G.
Again, just make sure you research all the kernels available for your device, and know what you're getting yourself into before you flash. Most phones should have a large forum thread somewhere on XDA or RootzWiki that lists all the kernels available for their device. Make sure you choose a compatible one, too—the version of Android you're running determines what kernels you can use, so make sure you don't flash a Sense kernel on an AOSP ROM (like CyanogenMod), and make sure you don't flash a Froyo kernel on a Gingerbread phone—they won't play nicely together.
How to Flash a New Kernel
Once you've found a kernel you want to flash, download it to your device. It should be in ZIP format. Flashing a kernel is almost exactly like flashing a new ROM. You'll need to flash a new recovery to your phone, like ClockworkMod, which you can flash with ROM Manager. Put the ZIP file on your phone's SD card, then start up ROM Manager and go to "Install ROM from SD Card". Choose the kernel's ZIP file and continue. Note, however, that some kernels require that you flash them through your recovery mode instead of with ROM Manager—so once again, do your due diligence on its home page before you go a-flashin'.
The main difference between flashing a ROM and flashing a kernel is that you do not want to wipe your data. Wipe the Dalvik Cache only, and back up your ROM if desired (I highly recommend doing so, in case something goes wrong). Other than that, you should be golden. If you haven't flashed a ROM before, I recommend reading up on that first—but if you're familiar with that process, flashing a kernel shouldn't be a big shock to the system.
SOURCE - - - Lifehacker.com
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thanks for sharing :good:
hi..
thx a lot for useful info for me as newbie. i'd like to req. permission to copy your info to my personal note..
i'm appreciated of your kindness.
TQ
Thanks, great information
Send From Samsung Galaxy S4
muchas gracias
zaki aziz said:
hi..
thx a lot for useful info for me as newbie. i'd like to req. permission to copy your info to my personal note..
i'm appreciated of your kindness.
TQ
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Yes you can copy.
Started from the bottom
tks it's usefful
do u recommand a kernel for best battery life?
i am using jammal rom and allucard kernel, but i only get 3460 scores and battery life is terrible. any tips?
Great info
Sent from my GT-I9500 using Tapatalk
Informative. Much appreciated.
245235568
There are plenty of apps in play store to disable wifi and 3G in order to optimize battery
i use zero lemon battery its great 7500 mAh lasts for days
kernel for best battery life?
Ive heard good things about talexop kernel
I also have zero lemon battery 7500 mAh I can get almost three days life on it without a charge
Sent from my SGH-I337M using Tapatalk
Hello .. after i instal an official lollipop using odin i notice that my battery mah drop from oroginal 2600mah to 2100mah i using many programs like aida64 and battery monitor widget and every program told me my battery is only 2100mah and i think the mah is reading from android kernel , i downgrade the phone back to kitkat 4.4.2 and the battery mah reading was correct and back again to 2600 so i think it was a mistake during the install of lollipop so i download the newer firmware available -I9515XXU1BOE3- and upgrade my firmware again but the problem come back again with wrong battery reading only 2100mah, i try to wipe the battery state and make calibration but nothing solved i downgrade the phone and upgrade it again and the problem appear every time ... could any one please help me how to solve this problem ... thanks in advance
hunter777 said:
Hello .. after i instal an official lollipop using odin i notice that my battery mah drop from oroginal 2600mah to 2100mah i using many programs like aida64 and battery monitor widget and every program told me my battery is only 2100mah and i think the mah is reading from android kernel , i downgrade the phone back to kitkat 4.4.2 and the battery mah reading was correct and back again to 2600 so i think it was a mistake during the install of lollipop so i download the newer firmware available -I9515XXU1BOE3- and upgrade my firmware again but the problem come back again with wrong battery reading only 2100mah, i try to wipe the battery state and make calibration but nothing solved i downgrade the phone and upgrade it again and the problem appear every time ... could any one please help me how to solve this problem ... thanks in advance
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It's normal. It's just wrong reading the battery capacity in lollipop. But, actually it is 2600mAh. It doesn't matter.
Sent from my Galaxy S4
I found undervolting could save up to 25% battery on my Nexus 4. I dropped it by 100mv which sounds a lot, but the device ran just as stable for I'd say 99% of the time. The only time I ever had a problem was if I started to take burst photos on the camera. I actually looked at recompiling the Camera apk to ramp up the the voltage ever so slightly.
:::fajri13::: said:
It's normal. It's just wrong reading the battery capacity in lollipop. But, actually it is 2600mAh. It doesn't matter.
Sent from my Galaxy S4
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thank you for your answer ... i want to know is this a common problem when upgrading to lollipop and if any one else face this problem with wrong mah battery capacity
hunter777 said:
thank you for your answer ... i want to know is this a common problem when upgrading to lollipop and if any one else face this problem with wrong mah battery capacity
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Do not worry, it is not a common problem but I had this some months ago on a leaked TW ROM. The problem fixed itself when I flashed CM12.1.
There is no impact on battery life.