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/t/ - tech

'technology is gay.' - Nelson Mandela

File: 1610812204572.png (36.72 KB, 400x400, rad.png)


Hey anon, I'm desperately need to tell you something about the xf86-video-ati driver. Well apperently, just recently I made a switch to use a linux libre kernel and it seems to work flawlessly on most of its free driver modules that can be loaded at boot into xorg server without kernel mode drm. The xf86-video-ati source code can be reach at its github here https://github.com/freedesktop/xorg-xf86-video-ati, there's also other alternative sources available which you can easily find it on the internet.

So, according to its shell man page documentation they provided, it only mention few option of modesettings modules that can be loaded into linux-libre kernel. The choices are "glamor", "exa" and "xaa" which being said that "xaa" it's an traditional technique of acceleration method according to https://manpages.ubuntu.com/manpages/precise/man4/radeon.4.html. I read somewhere about the glamor modules, supposely it is the highest end of xf86-video-ati module has to offer. Out of my curiousity, I did more analysis on it and finally figure out where the system fetched all these module files according to my xorg log until, I found out more undocumented driver modules available that can be loaded into config files.

All of these modules can be fetch from /usr/lib/xorg/modules

glamor 212.0 kb
int10 142.6 kb
wfb 134.9 kb
fb 110.9 kb
exa 94.7 kb
shadow 38.1 kb
gahw 35.1 kb
vbe 30.3 kb
fbdevhw 22.2 kb
shadowfb 14.1 kb


Looking at all these modules, I could used each one of them except glamor (I don't know why I'm getting segfault based from xorg log) and apply it in /usr/share/X11/xorg.conf.d/10-radeon.conf and /etc/X11/xorg.conf.d/20-radeon.conf. Btw, i'm using a RS880M 4225/4250 radeon hd laptop to test all these modules. Heres how my xorg configuration looks like in /usr/share/X11/ and /etc/X11/xorg.conf.d:


Section "OutputClass"
Identifier "Radeon"
MatchDriver "radeon"
Driver "modesetting"
Option "AccelMethod" "insert-your-prefered-driver-modules-here"


Section "Device"
Identifier "Radeon"
Driver "modesetting"
Option "AccelMethod" "insert-your-prefered-driver-modules-here"
Option "DRI" "3"
Option "ShadowPrimary" "on"
Option "MigrationHeuristic" "greedy"
Option "ColorTiling" "on"
Option "EnablePageFlip" "on"
Option "SWcursor" "on"
Option "AccelDFS" "off"


Looking back at xorg.log, it seems that the xorg server are ignoring the rest of the module options except from the 4th line where it invoked the driver module in /etc/X11/xorg.conf.d/20-radeon.conf. I personally believe that you can only customize your option module if you choose your "AccelMethod" as "none". This is explained on https://wiki.parabola.nu/ATI on how to invoke a customize option for modesetting. Still, there's not enough information describing each of these xorg modules. I can see all these option module automatically selected and loaded at runtime based from the xorg log once the 4th line its invoked, but it's hard to see what's the significant difference between each of these modules that can be invoked from /usr/lib/xorg/modules. If anyone know what int10, wfb and the rest of it means please do tell me. Also, I'm having issue on getting my keyboard and mouse functioning after got myself into lightdm login screen. I don't know which configuration are reponsible for this. The funny thing is when booting through livecd ISO, I don't get any of these particular issue on that matter. So yeah, please do tell me what how to fix this.


I've never messed w/ ati/amd display drivers so i have little to no clue in regards to messing around with the different modesets, though it honestly does sound real interesting, are the different modules like colour gradings and such?

In terms of LightDM messing up your devices, i believe it hooks into your xsession conf file, and i believe there is a way to identify certain peripherals via 'lsusb', at least on debian which im used to using, then getting the relevent device ID and adding it to one of your specific user devices, wish i could recall more specific information that that to help you but I know the kind of issue your having because I had the same but with secondary HDDs being mislabled once I began messing with my login manager gui settings. Will post all the debian links i used to recall the above info now, even though ik ur on an arch system, it should still help for looking up the equivalent info for your fork:

Hope this post is able to help even if its just a wee bit


I finally figure out about why there's no functioning pheripharals while in login screen. Apperently the dbus service doesn't run at boot runlevels. How on earth that wasn't configured beforehand I have no idea. I was looking for dbus error log and it's almost none existant until i started messing out with runlevel services. Damn this was so tiring to fix.

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