[Q] Device drivers in the Kernel or the ROM? - General Questions and Answers

I've been rooting phones for a few years and it always seems to amaze me how much different a device driver can be depending on what ROM is installed even with the same kernel. In most of my years as a sysadmin, many drivers are compiled into the kernel, but there are many that can be added during the init process.
My question is, how does the android kernel/ROM function in respect to drivers such as Bluetooth? Do most of the developers add them into the Kernel or as some piece of the ROM?
Thanks.
J

denalijb said:
I've been rooting phones for a few years and it always seems to amaze me how much different a device driver can be depending on what ROM is installed even with the same kernel. In most of my years as a sysadmin, many drivers are compiled into the kernel, but there are many that can be added during the init process.
My question is, how does the android kernel/ROM function in respect to drivers such as Bluetooth? Do most of the developers add them into the Kernel or as some piece of the ROM?
Thanks.
J
Click to expand...
Click to collapse
Appears I've answered my own question. I did some research and a few tests and this appears to be 90% in the kernel. On to my specific issue is that every new ROM or kernel I try for my SGS3 never seems to work correctly with bluetooth. I had heard samsung's driver is closed source, but I also remember it working perfectly in 4.2.2 ROMs.
I think it may be time to compile some source on my own.

Related

[Q] ASOP Sidekick 4G ROM?

Am I the only one who is unhappy with the slim pickings of ROMs that are available for the SK4G?
Does anyone know anything about an ASOP ROM?
It's AOSP (Android Open Source Project) and you're not the only one not happy with the current SK4G options. I personally want MIUI or CM7, but seeing as we're currently stuck with Froyo, we'll have to see what the devs can cook up.
Sent from my SGH-T839 using XDA App
For future reference, questions go in the General forum, not the Development Forum.
As for AOSP or MIUI, I know that AyoTeddy and Revolution are currently working on separate MIUI roms, and for AOSP, I'm working on that, but not sure exactly what you want from AOSP that's different from what we have?
If you are unhappy with the selection of ROMS here, you are always welcome to make your own, android is open source for a reason.
sduvick said:
For future reference, questions go in the General forum, not the Development Forum.
As for AOSP or MIUI, I know that AyoTeddy and Revolution are currently working on separate MIUI roms, and for AOSP, I'm working on that, but not sure exactly what you want from AOSP that's different from what we have?
If you are unhappy with the selection of ROMS here, you are always welcome to make your own, android is open source for a reason.
Click to expand...
Click to collapse
If they want the real miui we will need some sort of aosp gingerbread to start with and a custom CM7 kernel or something.. Since we dont have either yet I guess we'll have to make the best out of what we have now like we have been. But those wanting a taste of miui may like what I have planned for my next release.
Sent from my SGH-T959 using XDA App
ayoteddy said:
If they want the real miui we will need some sort of aosp gingerbread to start with and a custom CM7 kernel or something.. Since we dont have either yet I guess we'll have to make the best out of what we have now like we have been. But those wanting a taste of miui may like what I have planned for my next release.
Sent from my SGH-T959 using XDA App
Click to expand...
Click to collapse
And so anticipation had set in, i can't wait ayoteddy. im very excited. SMX was great, and SMGC was awesome, and now with this? whewwww. think i better go lay down, lol.
I'm also interested in porting CM7 to Sk4g cause I'm used to when I had G1 and now I'm using Sk4g without it.
I have programming skill and understanding of linux architecture. I've read about android architecture and AOSP and how to build Cyanogen from source. I'm running a tech firm (about 30 employees) - we are developing games that's why I don't have enough time to port it faster but I'm going to do it in a month or two.
So, I need help from experienced dev for android who is willing to build AOSP rom for Sk4g.
Here is what I'm going to do:
1) I'm gonna try to build Kd1 rom from source (there is an opensource code from samsung) and flash it to my Sk4g
2) Change the platform in original source to AOSP 2.2 and remove all TMOBILE apps - then build and flash
3) I'll try to find all hardware specs of the phone to compare with other samsung devices. It can help to exctract proprietary drivers of the phone. I think that the drivers are commonly the same, but I need to identify it.
After that I'm gonna upgrade to AOSP 2.3 but I don't have enough knowledge right now. Can some experienced devs answer the questions:
1) Are the linux kernels of AOSP 2.2 and 2.3 identical?
2) Can I use device drivers from 2.2 on 2.3?
If someone is interested in this project - please let me know and let's start the job. I think that my progress wouldn't be fast due to lack of time.
Thank you for joining the Sidekick 4G section , & we welcome you but if you want you could pause the game's for the ROM if anything & Question 1 is a no & Question 2 no cause they have to be compiled with the 2.3 kernel .
- Said by Sduvick
jmpz said:
I'm also interested in porting CM7 to Sk4g cause I'm used to when I had G1 and now I'm using Sk4g without it.
I have programming skill and understanding of linux architecture. I've read about android architecture and AOSP and how to build Cyanogen from source. I'm running a tech firm (about 30 employees) - we are developing games that's why I don't have enough time to port it faster but I'm going to do it in a month or two.
So, I need help from experienced dev for android who is willing to build AOSP rom for Sk4g.
Here is what I'm going to do:
1) I'm gonna try to build Kd1 rom from source (there is an opensource code from samsung) and flash it to my Sk4g
2) Change the platform in original source to AOSP 2.2 and remove all TMOBILE apps - then build and flash
3) I'll try to find all hardware specs of the phone to compare with other samsung devices. It can help to exctract proprietary drivers of the phone. I think that the drivers are commonly the same, but I need to identify it.
After that I'm gonna upgrade to AOSP 2.3 but I don't have enough knowledge right now. Can some experienced devs answer the questions:
1) Are the linux kernels of AOSP 2.2 and 2.3 identical?
2) Can I use device drivers from 2.2 on 2.3?
If someone is interested in this project - please let me know and let's start the job. I think that my progress wouldn't be fast due to lack of time.
Click to expand...
Click to collapse
Revolution, thanks for relaying my responses.
jmpz, I tried building the source before, but was unable to build it completely, but that was possibly because of some errors with my dependencies. The kernel compiles fine from source, you just need to pull initramfs, or you can get it from Dr. Honk's github.
Thank you for your answers.
So, can anyone enumerate the list of drivers which we should extract from kernel?
I can name these:
1) Keyboard
2) Mic
3) 2 speakers
4) buttons
5) front camera
6) rear camera
7) trackpoint
8) lcd
9) digitizer
10) 3.5 jack
Please correct me and add missing
If I understanding it rightly the key problem is getting proprietary drivers from the kernel. Right?
nope, the key problem is trying to build the system entirely, without any errors, which may be easier with someone following a stock designed build environment. I don't use Ubuntu which is what has the listed dependencies for every tutorial I can find. You can get the drivers out of Dr. Honk's voodoo kernel ramdisk here: http://forum.xda-developers.com/showthread.php?t=1145139
There shouldn't be any problems if you just set up a build environment following the directions in any of the tutorials, then add the platform from the samsung source.
I'm a linuxoid - so these tutorial are for me. Thank you for the link.
By the way, drivers are in Linux Kernel, so I don't think that I need to use Samsung Platform from the source. Instead I wanna use platform from AOSP or Cyanogen. Correct me if I'm wrong.
I think that grabbing drivers from kernel source from samsung would be enough to build the rom.
jmpz said:
I'm also interested in porting CM7 to Sk4g cause I'm used to when I had G1 and now I'm using Sk4g without it.
I have programming skill and understanding of linux architecture. I've read about android architecture and AOSP and how to build Cyanogen from source. I'm running a tech firm (about 30 employees) - we are developing games that's why I don't have enough time to port it faster but I'm going to do it in a month or two.
So, I need help from experienced dev for android who is willing to build AOSP rom for Sk4g.
Here is what I'm going to do:
1) I'm gonna try to build Kd1 rom from source (there is an opensource code from samsung) and flash it to my Sk4g
2) Change the platform in original source to AOSP 2.2 and remove all TMOBILE apps - then build and flash
3) I'll try to find all hardware specs of the phone to compare with other samsung devices. It can help to exctract proprietary drivers of the phone. I think that the drivers are commonly the same, but I need to identify it.
After that I'm gonna upgrade to AOSP 2.3 but I don't have enough knowledge right now. Can some experienced devs answer the questions:
1) Are the linux kernels of AOSP 2.2 and 2.3 identical?
2) Can I use device drivers from 2.2 on 2.3?
If someone is interested in this project - please let me know and let's start the job. I think that my progress wouldn't be fast due to lack of time.
Click to expand...
Click to collapse
I 100% support your efforts. I want Cyanogen on the SK4G badly, but I'm not sure what kind of help a non-programmer like me could do, but do have some experience with flashing phones and such, so if there is anything you need let me know.
If you do get rolling heavily on this, I'd be willing to donate monetarily to your efforts.
If anyone can get CyanogenMod 7 on the Sidekick they would definetely get a donation from me. Id be thrilled. Glad to see its going to be worked on.
Sent from my Sidekick 4G using XDA Premium App!

[Q] Are all our GB ROMs based on LG GB Drivers?

Hi.
Might be retarded to ask this, but as the title says: are all the roms in the dev section (the ones' which are GB roms, of course) uses LG's drivers and 2.3GB?
Let me explain myself (if needed):
Recently I have found out that one obstacle in building the ICS ROMs is not having the LG drivers in order to "sit" the ROM on the hardware.
Ok. Great.
Now this makes me ask, what about the GB Roms? Are they all using the official LG drivers? Are they "based" on these driver?
I am assuming that a ROM which is basing itself on official LG drivers will be the most reliable, least likely to force-close, and so on.
Thanks!
I think so, and I'm pretty sure they are; even if it's the the degree that the original drivers are modified to some degree, such as a custom kernel. I wouldn't imagine that the drivers, except maybe for CM9, have been rewritten from the ground up.
This is my educated opinion and I may still be wrong.

[Q] Which kernel?

With all the custom hacks offered here, how do I figure out which kernel works with my device? Are all "Android" kernels running on ARM with the x86 instruction set?
Even if that were true, there must be more details involved with full compatibility.
The one thread which names my device is pretty much dead for months now.
(http://forum.xda-developers.com/showthread.php?t=1392593)
Which kernels could run on a Craig clp281?

[Q] Aosp and Kernel

I am building an aosp ROM for the galaxy player 5.0 as an independent study at my school. I have the stock kernel for it that I extracted out of an odin image and I was wondering, do I have to build aosp around the kernel because I heard aosp kernels aren't good with the drivers and I need every function to work. I have found many tutorials for aosp and I am not going to use Googles since I can't understand that as much as other ones on the internet. Can someone enlighten me on the subject so I'm not going to fail, its due by january and I am still on the fence about whether I can do this. I just need some guidance and not to have somebody do it for me.

[Q] LG Volt

Hello! I have the Boost Mobile LG Volt and I am somewhat of a noob but smart enough to get it rooted on V4 using a rollback guide and towelroot. My problem is i hate the stock kernel and hate not having voltage control. Is there a flashable package that i can use to add voltage control and all of the other fun things that come with a custom kernel? Ive seen guides on porting roms to my device and they seem fairly simple since its just editing a zip with all custom stuff and leaving the sys files alone. Again the kernel!!! Ive tried flashing so many diffrent kernels but they all softbrick my phone
I love this phone. With root i have CPU settings so it lasts 3 days heavy use. I want more !!! Please help!!!
The stock kernel for this phone is available on githubhttps://github.com/chevanlol360/Kernel_LGE_X5
And from what im reading kernels must be device tailored?
SPHM900 said:
And from what im reading kernels must be device tailored?
Click to expand...
Click to collapse
yes sir they do. development is still in its infancy, there are people working on cyanogenmod right now, but they "JUST" got audio support, so you may want to wait a minute. There are a few custom roms available, just takes a lil google-fu.
Also you are very lucky to still have a working phone, careful with those kernels.

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