Re: Psychedelic GUI after stable update to buster

[hobie@rumormillnews.com]

> On 14.07.2019 12:02, hobie@rumormillnews.com wrote:
>>> On 14.07.2019 4:20, Felix Miata wrote:
>>>> hobie@rumormillnews.com composed on 2019-07-13 18:07 (UTC-0400):
>>>>
>>>>> Thanks for the tip.  Looks like a lot of information here but I don't
>>>>> really understand it.  Xorg seems to have unloaded the radeon
>>>>> driver...?
>>>>> Graphics:  Device-1: AMD Kaveri [Radeon R7 Graphics] vendor: ASUSTeK
>>>>> driver: N/A
>>>>>            bus ID: 00:01.0 chip ID: 1002:130f
>>>>>            Display: x11 server: X.Org 1.20.4 driver: ati,vesa
>>>>>            unloaded: fbdev,modesetting,radeon resolution:
>>>>> 1600x900~N/A
>>>>>            OpenGL: renderer: llvmpipe (LLVM 7.0 128 bits) v: 3.3 Mesa
>>>>> 18.3.6
>>>>>            compat-v: 3.1 direct render: Yes
>>>>> Where would I find "AMDGPU" and how would I get Xorg to use it?
>>>> These should cover it:
>>>> apt purge xserver-xorg-video-ati xserver-xorg-video-radeon
>>>> apt install xserver-xorg-video-amdgpu firmware-amd-graphics
>>> To install "firmware-amd-graphics" package is a good suggestion.
>>> But chances are high that removal of *-ati and *-radeon packages will
>>> also remove Desktop Environment, because those packages are part of
>>> "xserver-xorg-video-all" package.
>>> I'd suggest a less radical approach and simply "tell" the system what
>>> driver to use via modprobe config files. [1]
>> Thanks. :)  I find old files in /etc/modprobe.d:
>>
>> -rw-r--r-- 1 root root  154 Nov 29  2016 amd64-microcode-blacklist.conf
>> -rw-r--r-- 1 root root   23 Apr 28  2011 i915-kms.conf
>> -rw-r--r-- 1 root root  154 May 15  2017 intel-microcode-blacklist.conf
>> -rw-r--r-- 1 root root   51 May 10  2014 modesetting.conf
>> -rw-r--r-- 1 root root  292 Aug  3  2012 nvidia-kernel-common.conf
>> -rw-r--r-- 1 root root  119 Nov 12  2013 oss-compat.conf
>> -rw-r--r-- 1 root root   27 Jan 19  2014 radeon-kms.conf
>>
>> ...I find radeon-kms.conf contains: "options radeon modeset=-1".  Is
>> that
>> likely where my problem, or part of my problem, is coming from?
>>
>>
> Kernel mode setting (modeset) is often required to be enabled with
> recent kernels. "-1" usually means "auto".
> "radeon-kms.conf" is not part of any package in stretch, so I assume it
> was manually created or a leftovers of some sort from previous system
> upgrades.
>
> The safest approach to test if switching to "amdgpu" driver will help,
> would be adding kernel module parameters at boot time.
> Press "e" to edit grub menu entry and add parameters to "linux" line
> after "quiet" parameter:
>
> amdgpu.si_support=1 amdgpu.cik_support=1 radeon.si_support=0
> radeon.si_support=0
>
> and continue to boot your system by pressing F10.

I did the edit you suggested - changing the *.si to *.cik on that second
readeon reference - but can't tell if anything was affected by it. 
Psychedelic colors still return on leaving the desktop and coming back to
it, and output of inxi -Gxxxz also appears the same:

Graphics:
  Device-1: AMD Kaveri [Radeon R7 Graphics] vendor: ASUSTeK
  driver: N/A bus ID: 00:01.0 chip ID: 1002:130f
  Display: x11 server: X.Org 1.20.4 driver: ati,vesa
  unloaded: fbdev,modesetting,radeon resolution: 1600x900~N/A
  OpenGL: renderer: llvmpipe (LLVM 7.0 128 bits)
  v: 3.3 Mesa 18.3.6 compat-v: 3.1 direct render: Yes

Also, I've moved all files from /etc/modprobe.d to a backup directory;
their absence does not appear to have made any difference, either.

--hobie