drm/i915: Fix crash when failing to parse MIPI VBT

Browse source

This particular nasty presented itself while trying to register the
intelfb device (intel_fbdev.c). During the process of registering the device
the driver will disable the crtc via i9xx_crtc_disable. These will
also disable the panel using the generic mipi panel functions in
dsi_mod_vbt_generic.c. The stale MIPI generic data sequence pointers would
cause a crash within those functions. However, all of this is happening
while console_lock is held from do_register_framebuffer inside fbcon.c. Which
means that you got kernel log and just the device appearing to reboot/hang for
no apparent reason.

The fault started from the FB_EVENT_FB_REGISTERED event using the
fb_notifier_call_chain call in fbcon.c.

This regression has been introduced in

commit d3b542fcfc
Author: Shobhit Kumar <shobhit.kumar@intel.com>
Date:   Mon Apr 14 11:00:34 2014 +0530

    drm/i915: Add parsing support for new MIPI blocks in VBT

Cc: Shobhit Kumar <shobhit.kumar@intel.com>
Signed-off-by: Rafael Barbalho <rafael.barbalho@intel.com>
Reviewed-by: Shobhit Kumar <shobhit.kumar@intel.com>
[danvet: Add regression citation.]
Cc: stable@vger.kernel.org
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

...

This commit is contained in:

Rafael Barbalho 2014-07-24 15:16:12 +01:00 • committed by Daniel Vetter

parent 274fa1c1ac

commit ed3b667993

1 changed files with 1 additions and 1 deletions

Show all changes Ignore whitespace when comparing lines Ignore changes in amount of whitespace Ignore changes in whitespace at EOL

Download patch file Download diff file Expand all files Collapse all files

2

drivers/gpu/drm/i915/intel_bios.c

View file