Database Info

Full 24 hours out of the stock battery with 4G

{
"lightbox_close": "Close",
"lightbox_next": "Next",
"lightbox_previous": "Previous",
"lightbox_error": "The requested content cannot be loaded. Please try again later.",
"lightbox_start_slideshow": "Start slideshow",
"lightbox_stop_slideshow": "Stop slideshow",
"lightbox_full_screen": "Full screen",
"lightbox_thumbnails": "Thumbnails",
"lightbox_download": "Download",
"lightbox_share": "Share",
"lightbox_zoom": "Zoom",
"lightbox_new_window": "New window",
"lightbox_toggle_sidebar": "Toggle sidebar"
}
So with the stock battery, 4g on, background data syncing on (twitter every 15 mins, fb every hour, push gmail, weather every hour) 20 mins of GPS usage, some youtube, some Words With Friends, some Angry Birds, lots of texting and tweeting, and about 45 minutes of actual talking on the phone, installing about 20 apps, and setting up about 10 of them... and its still going, no there isn't much left at all, 5%, but the battery life isn't as horrible as everyone is making it out to be. Every type of data transfer or sync or stream was done over 4g, I never turned the 4G radio off at all, never disabled background sync, any of that. I did have the "power saver" mode come on at 15%, but by that time I was already over 22 hours on the battery.
This was with Adryn kernel and BAMF 1.1 rom. SetCPU profile only for screen off, 245/245. If I can get a solid 24 hours out of a very lightly *tweaked* stock rom and kernel, I can only imagine how good it could get a few months from now.
BTW I have a pretty constant -62 db rating for LTE, which is amazing if you ask me.

Pretty awesome. I also set a setcpu for 245mhz min/max when the screen is off. But i keep messing with the phone to haveit last that long lol.
I also have mines exclusively in 4G mode. LTE is a beautiful thing. OHHH
Also...
I installed spare parts and set the animations and transitions to "fast". ive been showing my friends. This phone is "flying". everything keeps up with it too.

Glad you can. Sadly, every device is different :/ I get about 10 hours out of mine. Although, that's just an estimate. I haven't let it drop low enough to test (usually plug in ~ 50%-60%)

g00s3y said:
So with the stock battery, 4g on, background data syncing on (twitter every 15 mins, fb every hour, push gmail, weather every hour) 20 mins of GPS usage, some youtube, some Words With Friends, some Angry Birds, lots of texting and tweeting, and about 45 minutes of actual talking on the phone, installing about 20 apps, and setting up about 10 of them... and its still going, no there isn't much left at all, 5%, but the battery life isn't as horrible as everyone is making it out to be. Every type of data transfer or sync or stream was done over 4g, I never turned the 4G radio off at all, never disabled background sync, any of that. I did have the "power saver" mode come on at 15%, but by that time I was already over 22 hours on the battery.
This was with Adryn kernel and BAMF 1.1 rom. SetCPU profile only for screen off, 245/245. If I can get a solid 24 hours out of a very lightly *tweaked* stock rom and kernel, I can only imagine how good it could get a few months from now.
BTW I have a pretty constant -62 db rating for LTE, which is amazing if you ask me.
Click to expand...
Click to collapse
I had my screen set with setcpu to 245/245 but I was getting lag when trying to unlock the phone from a blank screen

Hmm, interesting enough. I can get roughly 13-15 hours out of it on a daily basis. No charge, moderate amount of surfing.

Strife21 said:
I had my screen set with setcpu to 245/245 but I was getting lag when trying to unlock the phone from a blank screen
Click to expand...
Click to collapse
I get a tiny bit, but its nothing that really bothers me.

Setting the CPU down that low doesn't lag out all your sync'ing? I sync a ton of RSS feeds as well (like 500+ posts a day). I have facebook, gmail, and twitter sync'ing all day too.
Only android experience I have is a Hero, and it was only like 350MHz full speed, so, lol, I remember what it was like using that. Just wondering how it affects syncs.
laters

I just configured SetCPU with the screen off 245/245 profile today, been running about 5.5 hours now, been playing music for about 3, battery is down to 65%, so definitely seeing an improvement

drod2169 said:
Glad you can. Sadly, every device is different :/ I get about 10 hours out of mine. Although, that's just an estimate. I haven't let it drop low enough to test (usually plug in ~ 50%-60%)
Click to expand...
Click to collapse
Battery depletion, or more to the point, the battery gauge, isn't linear. I bet you get noticeably more from the bottom50% than the top.
Sent from my ADR6400L using XDA App

4g is more efficient per byte than 3g is. As in, transfering 100mb over 4g is going to use less battery than transferring 100mb over 3g. Even though second for second 4g uses more battery than 3g. As in running 4g for 5 seconds uses more battery than 3g, but you get way more done in those 5 seconds on 4g than you do on 3g.
I wouldn't turn off 4g unless I'm in a fringe area.

That's a nice battery life. I'm gonna try tweaking mine to see if I can get anything like that.

very nice tip.
Thanks

Battery life low since I root+flashed

Hello, I rooted and flashed CM and now AOKP. Under both, my battery life is low compared to when I had stock.
I have not flashed my radio or kernel, maybe that's it? I noticed my network signal is kind of low, too.
Here's a shot of my battery life:
{
"lightbox_close": "Close",
"lightbox_next": "Next",
"lightbox_previous": "Previous",
"lightbox_error": "The requested content cannot be loaded. Please try again later.",
"lightbox_start_slideshow": "Start slideshow",
"lightbox_stop_slideshow": "Stop slideshow",
"lightbox_full_screen": "Full screen",
"lightbox_thumbnails": "Thumbnails",
"lightbox_download": "Download",
"lightbox_share": "Share",
"lightbox_zoom": "Zoom",
"lightbox_new_window": "New window",
"lightbox_toggle_sidebar": "Toggle sidebar"
}
And here's my BBS log: https://dl.dropboxusercontent.com/u/92536272/BetterBatteryStats-2013-10-16_002712036.txt
I'm always on wifi, always was and never had problems with that. Didn't install any new apps I didn't have before root apart from UCCW and the holo glass theme with an icon pack, everything else (which is not much, maybe a few more apps along with gapps) was there before.
I am at your mercy , android gods.

Posklapenzi said:
Hello, I rooted and flashed CM and now AOKP. Under both, my battery life is low compared to when I had stock.
I have not flashed my radio or kernel, maybe that's it? I noticed my network signal is kind of low, too.
Here's a shot of my battery life:
And here's my BBS log: https://dl.dropboxusercontent.com/u/92536272/BetterBatteryStats-2013-10-16_002712036.txt
I'm always on wifi, always was and never had problems with that. Didn't install any new apps I didn't have before root apart from UCCW and the holo glass theme with an icon pack, everything else (which is not much, maybe a few more apps along with gapps) was there before.
I am at your mercy , android gods.
Click to expand...
Click to collapse
I read your log. These are the major consumers of your battery:
Wifi On (): 8 h 37 m 18 s (31038 s) Ratio: 100.0%
Wifi Running (): 8 h 37 m 18 s (31038 s) Ratio: 100.0%
No Data Connection (): 8 h 37 m 18 s (31038 s) Ratio: 100.0%
No or Unknown Signal (): 8 h 37 m 18 s (31038 s) Ratio: 100.0%
Since you already know that wifi is not an issue, then the other would have been the cause.
Low network signal is one of the causes of low battery life. When the network signal is low, your cellphone increases its transmitting power incrementally until it gets a signal of a preset threshold (set by the radio). It will keep on transmitting at frequent intervals to establish a link with the cellular base station, and this is where the battery consumption lies. When a cellphone transmits, it uses as much as 15 time more power than when it is just on receive mode. You could try the following steps to narrow down to where the problem lies.
1. If you have always been in the same location before and after flashing the new ROM, then it could be the network provider's problem because the cellular base station may not be working properly, hence the low signal. Ask around someone else around you who is on the same network and see it he also have this low signal problem. If others have the same problem, then call the network provider to complain.
2. If you have changed location since flashing, then you might be in a location that has low signal levels. Again, you can also check with others if they encounter the similar problems. Same as above, call the network provider to complain.
3. If others around you do not have network signal issues and you are the only one, then it is probably the ROM. If you can, revert to the OEM and compare. If, after reverting to OEM and the problem still exist, then you can try to upgrade the radio ROM.
4. If after upgrading your radio ROM and the problem is still there, then it is probably your phone hardware. I will advise to send to OEM for an evaluation and repair if necessary.
Hope this helps.

chan.sk said:
I read your log. These are the major consumers of your battery:
Wifi On (): 8 h 37 m 18 s (31038 s) Ratio: 100.0%
Wifi Running (): 8 h 37 m 18 s (31038 s) Ratio: 100.0%
No Data Connection (): 8 h 37 m 18 s (31038 s) Ratio: 100.0%
No or Unknown Signal (): 8 h 37 m 18 s (31038 s) Ratio: 100.0%
Since you already know that wifi is not an issue, then the other would have been the cause.
Low network signal is one of the causes of low battery life. When the network signal is low, your cellphone increases its transmitting power incrementally until it gets a signal of a preset threshold (set by the radio). It will keep on transmitting at frequent intervals to establish a link with the cellular base station, and this is where the battery consumption lies. When a cellphone transmits, it uses as much as 15 time more power than when it is just on receive mode. You could try the following steps to narrow down to where the problem lies.
1. If you have always been in the same location before and after flashing the new ROM, then it could be the network provider's problem because the cellular base station may not be working properly, hence the low signal. Ask around someone else around you who is on the same network and see it he also have this low signal problem. If others have the same problem, then call the network provider to complain.
2. If you have changed location since flashing, then you might be in a location that has low signal levels. Again, you can also check with others if they encounter the similar problems. Same as above, call the network provider to complain.
3. If others around you do not have network signal issues and you are the only one, then it is probably the ROM. If you can, revert to the OEM and compare. If, after reverting to OEM and the problem still exist, then you can try to upgrade the radio ROM.
4. If after upgrading your radio ROM and the problem is still there, then it is probably your phone hardware. I will advise to send to OEM for an evaluation and repair if necessary.
Hope this helps.
Click to expand...
Click to collapse
Thank you very much for your help kind sir I have not changed location. I agree that revering and comparing might be a good place to strat, although I am partial to skipping that step and just flashing a new radio in the hopes of that fixing it

GPS keeping apps awake, even though GPS is off and apps are greenified.

I'm having an issue where apps which require location seemingly stay awake after being greenified and killed from the recent apps. In my battery stats, it shows the gps use details going up continuously, while the CPU usage does does not.
I am running the stock ROM and trinity kernel.
{
"lightbox_close": "Close",
"lightbox_next": "Next",
"lightbox_previous": "Previous",
"lightbox_error": "The requested content cannot be loaded. Please try again later.",
"lightbox_start_slideshow": "Start slideshow",
"lightbox_stop_slideshow": "Stop slideshow",
"lightbox_full_screen": "Full screen",
"lightbox_thumbnails": "Thumbnails",
"lightbox_download": "Download",
"lightbox_share": "Share",
"lightbox_zoom": "Zoom",
"lightbox_new_window": "New window",
"lightbox_toggle_sidebar": "Toggle sidebar"
}
Sent from my Nexus 5 using Tapatalk

ikn0wagh0st said:
I'm having an issue where apps which require location seemingly stay awake after being greenified and killed from the recent apps. In my battery stats, it shows the gps use details going up continuously, while the CPU usage does does not.
I am running the stock ROM and trinity kernel.
View attachment 2623869
Sent from my Nexus 5 using Tapatalk
Click to expand...
Click to collapse
I don't see the little GPS peg on the screen that would indicate GPS is being used. Is your battery dropping fast? It's either a bug in the display, or a bug in the GPS code.

Aerowinder said:
I don't see the little GPS peg on the screen that would indicate GPS is being used. Is your battery dropping fast? It's either a bug in the display, or a bug in the GPS code.
Click to expand...
Click to collapse
That is correct, and why I am baffled. GPS is turned off. Battery life seems fine from what I am seeing.

ikn0wagh0st said:
That is correct, and why I am baffled. GPS is turned off. Battery life seems fine from what I am seeing.
Click to expand...
Click to collapse
Is the issue reproducible?

go to your phones main settings, location.. what mode is it in? high accuracy, battery saving, or device only? also is googles location reporting on or off?

ikn0wagh0st said:
That is correct, and why I am baffled. GPS is turned off. Battery life seems fine from what I am seeing.
Click to expand...
Click to collapse
It happened with me also some days back, location services were completely off but google services kept gps on, while I didn't enable it and I was able to track down the culprit, for me it was google play services. Restart fixed it for me.
I think this is another bug because same thing happened with a person who I know and for him it was facebook and for you its speedtest app.

I've noticed the service GoogleLocationManager tries to keep itself running at all times, even with locations completely disabled.
Sent from my Nexus 5 using Tapatalk

Hi, i have the same problem. Few days ago i found out that may GPS si running background even if my google location, google maps are off. I put phone into airplane mode but GPS was still running.
My nexus 5 is stock and unrooted. If i turn off/on GPS stop running.
Has anyone any solution about this problem?it seems it has to be some bug draining my battery, but if i dont root nexus i wont know wick app is draining battery?

simms22 said:
go to your phones main settings, location.. what mode is it in? high accuracy, battery saving, or device only? also is googles location reporting on or off?
Click to expand...
Click to collapse
^^^^^ this.
Set it to battery saving. A majority of the apps do not need high accuracy (active) GPS. The only time I have to enable High accuracy active GPS is when using maps/navigation (a tasker profile takes care of that for me - enable high accuracy when maps is launched, and switch to battery saving when I exit maps). Most of the other apps work just fine with battery saving location settings.

I got this issue today ( stock rooted)
After using the map and GPS for many hours, the GPS was awake even after force close the map app, and setting location off.
Rebooting the phone is the fix.

1.5hr SOT - I must be doing something..

Hey there,
So I've had my Nexus 5 for quite some time now and tried a few different ROMs and Kernel combinations. I care a LOT about battery life but this device has never really kept up to what others are saying it's capable of.
ROM: OmniROM latest nightly
Kernel: Faux123 Kernel v013
I'm currently getting around 1.5 hours of screen on time of use with no 'battery saving' apps, no greenify, location reporting on. The only setting I've changed is make GPS set to battery saving. Is this normal? Android OS takes up 30% of the battery stats. I have also attempted a full factory reset and built it from scratch (not restoring any backups) with no change.
Any help is greatly appreciated,
Thanks!

use better battery stats and give us that info.

You have the Android OS disease
Sent from my Nexus 5 using Tapatalk

DarkRyoushii said:
Hey there,
So I've had my Nexus 5 for quite some time now and tried a few different ROMs and Kernel combinations. I care a LOT about battery life but this device has never really kept up to what others are saying it's capable of.
ROM: OmniROM latest nightly
Kernel: Faux123 Kernel v013
I'm currently getting around 1.5 hours of screen on time of use with no 'battery saving' apps, no greenify, location reporting on. The only setting I've changed is make GPS set to battery saving. Is this normal? Android OS takes up 30% of the battery stats. I have also attempted a full factory reset and built it from scratch (not restoring any backups) with no change.
Any help is greatly appreciated,
Thanks!
Click to expand...
Click to collapse
1) Set screen brightness manually.
2) Turn location reporting to high accuracy or device only, or even off.
3) Don't agree to Google location reporting.
4) Turn off Wifi background scanning (Settings, Wifi, Menu->Advanced, Scanning always Available unchecked)
5) I find Wi-Fi optimization off may or may not help.
6) Make sure you get good signal strength. If you need to, downgrade to 3g (EVDO, not HSPA) if Sprint from LTE if the signal is better, or even 2g (edge, not 1x) if T-Mobile.
7) Disable unnecessary syncing for your accounts (Google Play ...).

you bought the wrong phone if you care allot about battery life.
Though what your getting is abnormal, im easily able to get 4 hours screen on time with heavy use

First - disable location reporting (leave location on. I do)
Download this - https://play.google.com/store/apps/details?id=cn.wq.disableservice
And make Google play services look like this -
{
"lightbox_close": "Close",
"lightbox_next": "Next",
"lightbox_previous": "Previous",
"lightbox_error": "The requested content cannot be loaded. Please try again later.",
"lightbox_start_slideshow": "Start slideshow",
"lightbox_stop_slideshow": "Stop slideshow",
"lightbox_full_screen": "Full screen",
"lightbox_thumbnails": "Thumbnails",
"lightbox_download": "Download",
"lightbox_share": "Share",
"lightbox_zoom": "Zoom",
"lightbox_new_window": "New window",
"lightbox_toggle_sidebar": "Toggle sidebar"
}
See how that helps
Sent from my Nexus 5 using Tapatalk

Your battery drain is certainly anomalous. I leave everything on all the time and average 22 hrs up with 5 hrs SOT. As @Zepius said, you need BBS logs to be able to troubleshoot.

Using that disabling app and using common sense you can also scrap off the location calling of other apps that really don't need it -
Sent from my Nexus 5 using Tapatalk

Thanks for the help guys but I haven't had much better luck, I didn't get a screenshot but today it lasted 9 hours with 1 hour screen on time.. there's definitely something wrong and even after a factory reset it's still not improving.
After running BBS today I got two that showed up as potential culprits.
bam_dmux_wakelock and wlan_rx_wake. Neither of these are linked to a specific app though.
Maybe time to call Google? I went through 4 Nexus 4 devices because of various issues.. maybe I need a second Nexus 5.

why dont you try just stock and see if its different?

Zepius said:
why dont you try just stock and see if its different?
Click to expand...
Click to collapse
I have, stock with my apps is just the same but I doubt it's an app, I have the exact same apps on my Note II (Backup synced from google when I reset the note) and that lasts days..

DarkRyoushii said:
I have, stock with my apps is just the same but I doubt it's an app, I have the exact same apps on my Note II (Backup synced from google when I reset the note) and that lasts days..
Click to expand...
Click to collapse
are you sure its not a badly coded app? the note II is not on kitkat if i remember correctly.
go with stock rom, stock kernel, and minimal apps for the day and see if there's a difference.

Zepius said:
are you sure its not a badly coded app? the note II is not on kitkat if i remember correctly.
go with stock rom, stock kernel, and minimal apps for the day and see if there's a difference.
Click to expand...
Click to collapse
Daily both are running OmniROM with the same set of apps, get home from a day of uni and the Nexus is on 30% while the Note is on 72% both with an hour of usage each.

DarkRyoushii said:
Daily both are running OmniROM with the same set of apps, get home from a day of uni and the Nexus is on 30% while the Note is on 72% both with an hour of usage each.
Click to expand...
Click to collapse
you're comparing phones with massively different size batteries.
will you just try what i asked?

Try a different kernel?
Sent from my Nexus 5 using Tapatalk

Certain routers or network settings can destroy batteries on wifi also. Kinda sounds like that's what your wakelocks could be from.
But yeah....before talking exchange or repair....you really need to reflash a clean stock version.....no installed apps and see how it is. If its an app or a router/network issue, the next phone will be the same.
Sent from my N5, N7, Moto X, G Tab 3 or S2.....

Boot into safe mode and see if it goes away. That's what Google support would suggest you to try.
Sent from my Nexus 5 using Tapatalk

Help finding/fixing idle battery drain

Hi my wife bought a Note 5 two days ago (9/30). She did all setup, app restoring, etc that evening and fully charged the phone overnight. However her phone is experiencing idle drain that I need some help fixing.
Some other info: battery saver modes are off, wifi is always on (but only connected at home), bluetooth is always off.
10/1: Arrived at work with 100% battery
A little over 4 hours later, with light use, the phone was at 51% with less that 45 mins SOT
{
"lightbox_close": "Close",
"lightbox_next": "Next",
"lightbox_previous": "Previous",
"lightbox_error": "The requested content cannot be loaded. Please try again later.",
"lightbox_start_slideshow": "Start slideshow",
"lightbox_stop_slideshow": "Stop slideshow",
"lightbox_full_screen": "Full screen",
"lightbox_thumbnails": "Thumbnails",
"lightbox_download": "Download",
"lightbox_share": "Share",
"lightbox_zoom": "Zoom",
"lightbox_new_window": "New window",
"lightbox_toggle_sidebar": "Toggle sidebar"
}
With facebook as the biggest offender I suggested she turn off the setting of pre-loading pics and videos.
When she got home she charged phone to 100%. I also changed mobile network to CDMA/LTE. Here's how the battery looked with light use before going to bed:
10/2 - Left the phone unplugged over night to see what would happen, it lost 12% sitting on the nightstand for 8 hours.
Will report back later this afternoon to see how the day is progressing.

First step for me in reducing battery drain was to disable the Facebook app. It is a battery hog and was always at the top of my list. Instead, use a browser and create a shortcut to facebook.com or install Metal from the Play Store which is a web wrapper for Facebook and so much lighter. Sometimes I still get strange battery drain from Android system (up to 35% sometimes!). But this usually gets resolved just by opening up recent apps and closing all.

Hmm, I don't have problems with Facebook app on my droid turbo

tripjnj said:
First step for me in reducing battery drain was to disable the Facebook app. It is a battery hog and was always at the top of my list. Instead, use a browser and create a shortcut to facebook.com or install Metal from the Play Store which is a web wrapper for Facebook and so much lighter. Sometimes I still get strange battery drain from Android system (up to 35% sometimes!). But this usually gets resolved just by opening up recent apps and closing all.
Click to expand...
Click to collapse
Some people want notifications.

Regardless, Facebook doesn't seem to be showing up at the top afte the setting change. I'm interested to see what she has this afternoon. Will have some updates screen shots later on. I also asked her to charge ~3pm then drive home with nav on to see what the battery looks like under heavy usage.
I need to dig into Android System to see what's going on there, any ideas? Will GSAM pro give more insight here?

Not looking good, 22% used in 2.5 hours with 20min SOT

One more

Where is the setting for turning off preload pics and videos in Facebook? I dont see it in the facebook app settings.

ultimatdan said:
Where is the setting for turning off preload pics and videos in Facebook? I dont see it in the facebook app settings.
Click to expand...
Click to collapse
I lied, facebook setting is "play videos automatically", I have to assume turning this off will save data/battery. Also Instagram has "use less data" setting. I thought I read that this stops pre-loading of videos/images, but I might have imagined that?
Anyway, for facebook setting hit the menu button next to the notifications icon then scroll to "App Settings" near the bottom of the screen.

After most of a work day and light use she's down to 58%. Looks like facebook is back up there, odd because it's not a problem on my phone.
Does anyone know how to troubleshoot why Android System is using so much battery?

I have a note 4 and I'm having similar issue ls

Hi I'm facing kind of same problem but other device HTC one m7 and rom is aicp I don't know what is draining battery in idle time but almost 10 to 20 % is gone in idle and the fun thing is I use airplane mod all the time
Sent from my One using Tapatalk

yogiboor said:
Hi I'm facing kind of same problem but other device HTC one m7 and rom is aicp I don't know what is draining battery in idle time but almost 10 to 20 % is gone in idle and the fun thing is I use airplane mod all the time
Sent from my One using Tapatalk
Click to expand...
Click to collapse
You guys have to also take in consideration the Lollipop total connection time bug. Apps open up a connection and it won't close it when it's done... For example my first charge cycle I signed into instagram and it used 40% of my battery without me ever open again. The total connection time of most apps ends up being hours when it shouldn't be. That won't be fixed untill Marshmallow comes to the Note 5. Google is aware and has fixed it. It's on multiple Lollipop devices.
Verizon Wireless Technician using Tapatalk on Note 5

Mine seems to die by every morning if I don't charge it over night

Jacob11701 said:
You guys have to also take in consideration the Lollipop total connection time bug. Apps open up a connection and it won't close it when it's done... For example my first charge cycle I signed into instagram and it used 40% of my battery without me ever open again. The total connection time of most apps ends up being hours when it shouldn't be. That won't be fixed untill Marshmallow comes to the Note 5. Google is aware and has fixed it. It's on multiple Lollipop devices.
Verizon Wireless Technician using Tapatalk on Note 5
Click to expand...
Click to collapse
I use greenify to hibernate apps but still some thing is going on but marshmallow is coming out soon so I am happy
Sent from my One using Tapatalk

Yea I've used that for a while. When I force stop an app I tend to not see it encounter that bug
Verizon Wireless Technician using Tapatalk on Note 5

If the device is rooted then you can try Greenify to hibernate the apps which are consuming the battery life.Try other simple solutions like disabling the Wifi and other tools when not using them.Sometimes Play services may cause the issue so try to fix them.There are some guides which may help you http://fixdroidbattery.net/fix-fast-battery-drain-problem-on-samsung-galaxy-note-5/
http://recomhub.com/blog/how-to-fix-samsung-galaxy-note-5-fast-battery-drain-problem/
Hope these guides will help you

The problem is ...because of the device used to be root although we flash original stock firmware it is still drain when device idle ...you can take a look in Android OS and see stay awake period ...one way is flash custom room that said deep sleep fix . Hope this comment could deal your problem