Bug 12627

Summary:	Endless Loop
Product:	xorg	Reporter:	Marc Haber <mh+freedesktop-bugs>
Component:	Driver/mga	Assignee:	Tilman Sauerbeck <tilman>
Status:	RESOLVED INVALID	QA Contact:	Xorg Project Team <xorg-team>
Severity:	normal
Priority:	medium	CC:	mh+freedesktop-bugs
Version:	7.3 (2007.09)
Hardware:	x86 (IA32)
OS:	Linux (All)
Whiteboard:
i915 platform:		i915 features:

Description Marc Haber 2007-09-30 09:42:37 UTC

Hi,

I have a matrox G450 connected via VGA to two TFT displays. 

In some situations, the driver seems to get stuck in an infinite loop. This most often happens when X comes up, or a KDE session is finished and the display manager kdm should take over again.

The X server does not respond to any signal short of SIGKILL, strace doesn't show anything, gdb can attach but not interrupt the process, and sometimes, on SIGKILL, the entire system crashes.

Please advise what to do how to debug this issue.

Greetings
Marc

Comment 1 Marc Haber 2007-09-30 09:49:33 UTC

Oh, yeah, I have Debian unstable with the driver from experimental:

(II) Module mga: vendor="X.Org Foundation"
# compiled for 1.4.0, module version = 1.9.99

Comment 2 Tilman Sauerbeck 2007-09-30 10:27:41 UTC

You're ssh'ing in from a second machine to run gdb, right? And I guess you run gdb as root, too?

Maybe this page can give you some clues:
http://wiki.debian.org/XStrikeForce/XserverDebugging

Comment 3 Marc Haber 2007-09-30 12:56:43 UTC

> You're ssh'ing in from a second machine to run gdb, right?

Yes.

> And I guess you run gdb as root, too?

Otherwise I wouldn't be able to attach.

> Maybe this page can give you some clues:
> http://wiki.debian.org/XStrikeForce/XserverDebugging

That web page gives a lot of general information about obtaining backtraces, but my X server does not crash. I am not sure whether it gives useful information about obtaining a backtrace from an endless loop.

One thing that might be interesting is that my X log is full of "(EE) MGA(0): [dri] Idle timed out, resetting engine..."

Comment 4 Marc Haber 2007-09-30 13:14:06 UTC

otoh, disabling DRI doesn't help the crash.

I also noticed that while the X server is running around in circles, I still have a mouse pointer and can move it, but that's about the only thing that I can still do on the local console. Even Ctrl-Alt-foo (with "foo" including "F1" and "Backspace") seems to be ignored.

Comment 5 Adam Jackson 2018-06-12 19:06:19 UTC

Mass closure: This bug has been untouched for more than six years, and is not
obviously still valid. Please reopen this bug or file a new report if you continue to experience issues with current releases.

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