linux-kernel - Any SYSRQ key to force mode switch to console mode when using KMS?

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Message-ID: <19601.1301.803816.92851@elektron.ikp.physik.tu-darmstadt.de>
Date:	Wed, 15 Sep 2010 19:40:37 +0200
From:	Uwe Bonnes <bon@...ktron.ikp.physik.tu-darmstadt.de>
To:	linux-kernel@...r.kernel.org
Subject: Any SYSRQ key to force mode switch to console mode when using KMS?

Hello,

is there any SYSRQ key that forces the video system to console mode,
especially when using KMS and allows to work on. 

Since going to KMS on a Thinkpad R50 with ATI Radeon RV250 via going from
Opensuse-11.2 to Opensuse-11.3 I experience frequent situations where I am
left with a black screen, with only ALT-SYSREQ-C switching the screen back
on and hard reboot as only chance to escape that situation.

Situations that result in a black screen are:

* Going with the mouse over the NOSCRIPT buttom in firefox. Load goes up and
screen goes black after some seconds. xorg.log ends with "Backtrace", but no
backtrace output...

* Calling pm-hibernate on a system that has hibernated before. First
  pm-hibernate/wake-up-per power buttom sequence is successfull.

Disabling KMS results in very slow "kaffeine" full screen output...

pm-hibernate and firefox/noscript worked pre-KMS on opensuse-11.2.

Some traces of other people hitting the NOSCRIPT xorg crash and others
hitting the black unresponsive screen with KMS on RV250 are
found on the net, but I didn't find a conclusive resolution.

Opensuse default kernel and the recent Opensuse 2.6.36-rc3 kernel-of-the day
were tested with no difference

Thanks

PS: I only follow linux-kernel via gmane.org, so if you need fast feedback,
please CC me. 
-- 
Uwe Bonnes                bon@...ktron.ikp.physik.tu-darmstadt.de

Institut fuer Kernphysik  Schlossgartenstrasse 9  64289 Darmstadt
--------- Tel. 06151 162516 -------- Fax. 06151 164321 ----------
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