chroot success: ? about Freedreno drivers

[edounn]

Hey everyone. Hope this is 'dev' enough.

I haven't seen anything anywhere about AT&T note3 chroots, other than AT&T N3 can not because of lack of boot loop. Anyway, I thought i'd mention that it works quite well with partition & Xsdl. I made a small post for the interested in the general forum.

To my question: has anyone tried the freedreno drivers? ~Github link~
I haven't been able to build it properly, it's missing some .o's. I have gcc working on my chroot.

I'm also having problems with pulse/alsa/gstreamer, I think it's a permission problem. The android audio user shows as aid_audio, but the dir /dev/socket/ shows as usr:Media/grp:audio and the socket is system/system. They're recognized as users in the chroot, but they're still unable to find get access to it. I couldn't get an alsa recording app on from playstore to connect to it either.

I'm kinda wondering if something funky with permissions after towelroot. I couldn't get su,chroot, etc to work properly until I got the system to recognize su as 'root' instead of uid:0. Once I got that everything for su started working? So, lost and confused. Ideas on what i'm doing wrong?

thanks!

 

[CalcProgrammer1]

I was able to build a kernel with DRM and KGSL DRM interface enabled, boot CM11 with it, open SSH in my Debian chroot, kill Android, and then attempt to run Xorg with the freedreno driver but I ended up getting a memory mapping error and a segfault.

The Note 3's panel is a command-mode DSI panel which means it will not automatically display what is written to /dev/graphics/fb0 like you would expect. Instead, you must call an ioctl (FBIOPAN_DISPLAY) to force a refresh of the display. The panel must be on for this to work. I'm not sure the exact sequence required to turn on the display but it involves opening /dev/graphics/fb0 and possibly mmap'ing it. If you use the fbdev Xorg driver it will turn on the panel, but you must then run a program to continuously send the FBIOPAN_DISPLAY ioctl to refresh it. This is non-accelerated and also seems to crash any GTK apps (only X11 basic apps like xterm worked, and even then the refreshing was glitchy).

I'm trying to tackle kexec-hardboot first because that will allow booting an entirely-Debian-focused kernel with the correct color mode and the DRM drivers and all. It will likely require some patches to the KGSL GPU code in the kernel, at least it did on my Note 1. Get on #freedreno on Freenode if you aren't already there, lots of knowledgeable people there to analyze logs and find patches. I got it working on my HP TouchPad and Note i717 with help from there.

 

[edounn]

Very nice, thanks!
I've only gotten fb to work on my nexus5.
Also thanks for the heads up on the freenode. Going to check it out.
Have you messed with sound at all?

Edit:
Wait, did you do this on a 900A? (I'm probably way behind times?)

 

[CalcProgrammer1]

N900T, so bootloader-unlocked. It will be doubly hard to do on the N900A since you'll have to compile as modules rather than just compile your own kernel, at least unless you guys get kexec (non-hardboot) working on the locked variants. You should be able to mess around with the framebuffer on the stock kernel just fine though, only the freedreno driver needs custom kernel changes.

I haven't messed around with sound at all. On my HP TouchPad I figured out how to use ALSA UCM files which set up the mixer controls. By default Android locks the sound devices so using them from a chroot while Android is running probably won't happen, but with Android out of the way you may be able to use them. I do know on the Note 1 and the HP TouchPad you have to load q6.xxx firmware files for the audio system to initialize during boot.

This file will be of interest when writing ALSA UCM files:

https://github.com/CyanogenMod/android_device_samsung_hlte-common/blob/cm-11.0/audio/mixer_paths.xml

I used the TouchPad's mixer_paths.xml file to write two UCM "verbs" - one to turn on internal speakers and one to turn on headphones. The UCM file basically sets the given switches to the given values and is basically just a reformatting of mixer_paths.xml. I was unable to find a mixer_paths.xml for the Note 1 and thus haven't messed with sound on it yet (it has to exist somewhere...).

 

[edounn]

N900T, so bootloader-unlocked. It will be doubly hard to do on the N900A since you'll have to compile as modules rather than just compile your own kernel, at least unless you guys get kexec (non-hardboot) working on the locked variants. You should be able to mess around with the framebuffer on the stock kernel just fine though, only the freedreno driver needs custom kernel changes.

I haven't messed around with sound at all. On my HP TouchPad I figured out how to use ALSA UCM files which set up the mixer controls. By default Android locks the sound devices so using them from a chroot while Android is running probably won't happen, but with Android out of the way you may be able to use them. I do know on the Note 1 and the HP TouchPad you have to load q6.xxx firmware files for the audio system to initialize during boot.

This file will be of interest when writing ALSA UCM files:

https://github.com/CyanogenMod/android_device_samsung_hlte-common/blob/cm-11.0/audio/mixer_paths.xml

I used the TouchPad's mixer_paths.xml file to write two UCM "verbs" - one to turn on internal speakers and one to turn on headphones. The UCM file basically sets the given switches to the given values and is basically just a reformatting of mixer_paths.xml. I was unable to find a mixer_paths.xml for the Note 1 and thus haven't messed with sound on it yet (it has to exist somewhere...).

Great thanks! That explains a few things with the boot lock. FB has been a total no go for me. I read something about the type of display not working with it? I have no idea if that's true, and can't seem to find that information right now. (it worked great on the my note2). If someone has gotten success let me know! I'll check out the UCM once more. I did get ALSA working with debian on the note 1, so that's the first thing I tried. My Touchpad, I thought, worked right out of the box. (I miss that thing!)

I'll give it shot tonight and see what I get. thanks a lot to both of you.

 

[CalcProgrammer1]

The Note 3's panel is a command mode panel while the Note 1's panel is video mode. I'm not sure about the Note 2 as I don't have one but if it worked for you it was likely video mode as well. In video mode it works like you'd expect any display to work - the framebuffer memory is automatically drawn to the screen at a fixed refresh rate (60Hz). A command mode panel is different, the framebuffer is only drawn to the display when it is commanded to, and thus the software has control over the refresh rate of the display. I did a test where I found the section of code in the Note 3's kernel where it does the software refresh and stuck a printk in there. I had the kmsg printing out over SSH while I swiped the screen around in Android. Sure enough, the printout only happened when I moved my finger and caused the framebuffer to update, the screen completely stopped refreshing otherwise.

I'm still trying to find a good solution to this, especially in regards to running kexec-hardboot and the kexecboot bootloader GUI. I've been able to get kexecboot to display by sticking an FBIOPAN_DISPLAY ioctl into the framebuffer sync function that kexecboot calls after it updates the screen. This ioctl seems to force the display to refresh, but only if certain conditions are met (and I'm unsure what all these conditions are). I do know that the LCD (actually AMOLED but it's listed as LCD panel in the code) must be powered on, the framebuffer must be open (i.e. call the open() function to /dev/graphics/fb0 and get a file descriptor), and possibly memory-mapped as well (the code I was using as a software refresher had mmap, though it might not be necessary). This is another thing to go to #freedreno for, a user there (crondog) has been working on Freedreno on the 2013 Nexus 7 which also has a command mode panel and he's done some software refresher work.