Bug 98631 - GPU lock ups when starting GDM, SDDM, and Plasma Desktop
Summary: GPU lock ups when starting GDM, SDDM, and Plasma Desktop
Status: NEW
Alias: None
Product: xorg
Classification: Unclassified
Component: Driver/nouveau (show other bugs)
Version: unspecified
Hardware: PowerPC Linux (All)
: medium blocker
Assignee: Nouveau Project
QA Contact: Xorg Project Team
URL:
Whiteboard:
Keywords:
Depends on:
Blocks:
 
Reported: 2016-11-07 19:52 UTC by Mingcong Bai
Modified: 2016-12-11 22:29 UTC (History)
1 user (show)

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Description Mingcong Bai 2016-11-07 19:52:59 UTC
Here on a PowerMac G5 with a NVIDIA GeForce 6600LE graphics card, most things run pretty well except for some of the things I wanted to run on the machine resulted in nouveau GPU lock-ups, and consequently a glitched display (artifacts only).

When trying to start GDM, SDDM, or Plasma Desktop on the machine, the display locks up, and I was able to salvage an error message as follows:

[drm] nouveau 0000:0a:00.0: GPU lockup - switching to software fbcon

After a minute or two, the display responds again, but only showing a black background with several randomly colored pixels, and some white blocks.

However, this graphics card runs LightDM, XFCE, MATE... and most other applications without such error and lock-ups. I was able to workaround the issue by using the nouveau.noaccel=1 kernel parameter (except in the case of GDM, it returned with the same error), but that simply beats the purpose of owning a graphics card.

However, even with the noaccel parameter in place, I was still experiencing bad coloring issues, as reported here: https://bugs.freedesktop.org/show_bug.cgi?id=98630.

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Some version info:

- Linux Kernel 4.8.6 (with 4K paging in case you are wondering)
- Mesa 13.0.0
- Xorg Server 1.18.4

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P.S.

I tried on with a Quadro FX4500, which simply shows the lock up error whenever attempting to start X. But I couldn't make sure if it's a hardware issue or not, as the card sparked on the first power up, that's why I have already returned it...
Comment 1 Ilia Mirkin 2016-11-07 19:58:55 UTC
Without trying to defend the suckiness, the nv30 driver is kinda crap and WAY lower quality than what these modern desktops expect. And that's on x86 -- BE PPC is largely untested, although I have made some efforts to get it kinda-working again.

Instead of booting with noaccel=1 you could try removing nouveau_dri.so. That way you still get the X-based accel, but nothing tries to use 3D accel.
Comment 2 Mingcong Bai 2016-11-07 20:16:12 UTC
(In reply to Ilia Mirkin from comment #1)
> Without trying to defend the suckiness, the nv30 driver is kinda crap and
> WAY lower quality than what these modern desktops expect. And that's on x86
> -- BE PPC is largely untested, although I have made some efforts to get it
> kinda-working again.

Please accept my applaud with your faster-than-light reply.

Where exactly could the latest efforts be obtained? I will be more than happy to test out the results with my machine (also, if you would need SSH access, I would quite happily provide that).

> Instead of booting with noaccel=1 you could try removing nouveau_dri.so.
> That way you still get the X-based accel, but nothing tries to use 3D accel.

I will try that later today, thanks very much!
Comment 3 Mingcong Bai 2016-11-07 21:52:29 UTC
As a follow up, after removing nouveau_dri.so, I no longer get GPU lock up when starting Plasma desktop.

However, I am still getting weird colors (for example, my KSplash setting has a background of dark green color, but it showed up as bright blue, and there is a black border around the KDE logo and the spinner (I will attach a photograph when I get back to my room).
Comment 4 poma 2016-11-08 10:58:14 UTC
Apropos Xfce 4.12, notice two variants of the Xfwm4:

= Xfwm4 4.12.3 "released" - Xrender driven compositor,
  it can be run on virtually any machine

$ xfwm4 --version
	...
	Build configuration and supported features:
	- Render support:                               Yes
	- Embedded compositor:                          Yes


= Xfwm4 "not released" - GL(X) driven compositor,
  https://git.xfce.org/xfce/xfwm4/commit/?id=fee08ea
  it can run on NV50 family (Tesla),
  https://nouveau.freedesktop.org/wiki/CodeNames/#NV50
  on e.g. NV30 is slow, i.e. not very useful,
  although it may have to do with the performance of the CPU.

$ xfwm4 --version
	...
	Build configuration and supported features:
	- Embedded compositor:                          Yes
	- Epoxy support:                                Yes



LightDM GTK+ Greeter (lightdm-gtk-greeter) is not accelerated,
therefore it can be run on virtually any machine.


KF5/KDE5 i.e. KWin also provides two variants of the compositor, GL and XRender driven.


One important difference is that Xrender driven compositors aren't tear-free.
Comment 5 Tomasz Paweł Gajc 2016-12-11 22:22:37 UTC
For me this sounds like #98039 related


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