Bug 25312

Summary:	Blanked screen with 2.6.37-rc6, -rc5 works OK (bisected to 541cc966915b6756e54c20eebe60ae957afdb537)
Product:	Drivers	Reporter:	Alex Villacis Lasso (avillaci)
Component:	Video(DRI - Intel)	Assignee:	drivers_video-dri-intel (drivers_video-dri-intel)
Status:	RESOLVED DUPLICATE
Severity:	normal	CC:	chris
Priority:	P1
Hardware:	All
OS:	Linux
Kernel Version:		Subsystem:
Regression:	Yes	Bisected commit-id:
Attachments:	lspci -vvvv on the affected machine. Kernel configuration used to compile affected kernel

Description Alex Villacis Lasso 2010-12-20 15:41:03 UTC

All mentioned computers run Fedora 14 x86_64 with KMS.

On my work machine with an Intel graphics chipset and a flat panel with working EDID, vanilla kernels 2.6.37-rc6 and 2.6.37-rc5 works OK.

On my home machine, with a somewhat different Intel graphics chipset, and a flat panel that does *not* report EDID information, 2.6.37-rc5 works OK but 2.6.37-rc6 blanks the KMS display on boot. I get the "no signal" message on the panel instead of a working display. I was able to bisect this to the following commit:

commit 541cc966915b6756e54c20eebe60ae957afdb537
Author: Chris Wilson <chris@chris-wilson.co.uk>
Date:   Mon Dec 6 11:24:07 2010 +0000

    drm: Don't try and disable an encoder that was never enabled
    
    Prevents code that assumes that the encoder is active when asked to be
    disabled from dying a horrible death.
    
    Reported-by: Daniel Vetter <daniel.vetter@ffwll.ch>
    Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
    Signed-off-by: Dave Airlie <airlied@redhat.com>

When I revert this commit, the problem goes away in my home machine.

Comment 1 Alex Villacis Lasso 2010-12-20 15:42:38 UTC

Created attachment 41012 [details]
lspci -vvvv on the affected machine.

Comment 2 Alex Villacis Lasso 2010-12-20 15:43:13 UTC

Created attachment 41022 [details]
Kernel configuration used to compile affected kernel

Comment 3 Alex Villacis Lasso 2010-12-20 15:49:06 UTC

Created freedesktop.org bug https://bugs.freedesktop.org/show_bug.cgi?id=32527

Comment 4 Chris Wilson 2010-12-22 12:44:37 UTC


*** This bug has been marked as a duplicate of bug 25242 ***