Bug 378027

Summary:	Start Plasma 5.9.4 with nouveau.noaccel=1 (no 3D acceleration)
Product:	[I don't know] kde	Reporter:	Ural <uralzima>
Component:	general	Assignee:	Unassigned bugs <unassigned-bugs-null>
Status:	RESOLVED NOT A BUG
Severity:	normal
Priority:	NOR
Version First Reported In:	unspecified
Target Milestone:	---
Platform:	Other
OS:	Linux
Latest Commit:		Version Fixed In:
Sentry Crash Report:

Description Ural 2017-03-24 17:56:48 UTC

I am tired of nouveau freeze and lockups. But don't want to switch to shitty nvidia binary driver. So I decided to disable any 3D acceleration, I don't need it. I have already configured XRender as my compositor, but when I boot with nouveau.noaccel=1, after login on sddm, plasma don't start. Segmentation fault on /usr/lib64/libexec/kf5/kscreen_backend_launcher.

Please help me totally disabling any acceleration in KDE PLasma 5.9.4.
Gentoo hardened, Linux 4.9.15

Comment 1 Christoph Feck 2017-03-24 18:14:36 UTC

You cannot. QtQuick requires OpenGL. If you have no functional OpenGL drivers, you can enable swrast Mesa driver, which does a slow(!!!) software emulation. Please ask in a forum of your distribution how to enable swrast.

Comment 2 Ural 2017-03-24 19:27:27 UTC

I already have mesa 13.0.5 and use 'XRender' as my default compositor to minimize any 3D activity (to avoid crash of nouveau)

I know it is slow, but the priority is not to freeze my 4 monitors. If I use 3D, every day twice I have total freeze of my GK106 with bunch of nouveau pgraph errors and only reset helps. Especially when a browser does some WebGL. No way to reload nouveau driver.  And this is with blobs, without blobs it working much worst. 

I did not found 'swrast' use flags in gentoo or something about it. I just have mesa installed. Can you please explain more? Or examples for other distrubutions, that I can adopt for gentoo. 
Thanks

Comment 3 Christoph Feck 2017-03-24 20:41:33 UTC

KWin compositing has nothing to do with OpenGL usage in QtQuick; changing to XRender only affects KWin, but not the Plasma shell.

Comment 4 Ural 2017-03-24 21:22:01 UTC

Thanks for clarification. Do I need to set 'swrast' somewhere in xorg.conf? 

localhost user # eselect mesa list
i915 (Intel 915, 945)
i965 (Intel GMA 965, G/Q3x, G/Q4x, HD)
r300 (Radeon R300-R500)
r600 (Radeon R600-R700, Evergreen, Northern Islands)
sw (Software renderer)
  [1]   classic
  [2]   gallium *

I have 2 options for mesa, classic and gallium.