[Intel-gfx] [PATCH v2 1/2] drm/i915: Don't dereference fb when disabling primary plane

[Chris Wilson]

On Wed, Aug 27, 2014 at 05:48:41PM +0300, ville.syrjala at linux.intel.com wrote:
> From: Ville Syrjälä <ville.syrjala at linux.intel.com>
> 
> During driver init we may not have a valid framebuffer for the primary
> plane even though the plane is enabled due to failed BIOS fb takeover.
> This means we have to avoid dereferencing the fb in
> .update_primary_plane() when disabling the plane.
> 
> The introduction of the primary plane rotation in
> 
>  commit d91a2cb8e5104233c02bbde539bd4ee455ec12ac
>  Author: Sonika Jindal <sonika.jindal at intel.com>
>  Date:   Fri Aug 22 14:06:04 2014 +0530
> 
>     drm/i915: Add 180 degree primary plane rotation support
> 
> caused a regression by trying to look up the pixel format before we can
> be sure there's a valid fb available. This isn't entirely unsurprising
> since the rotation patches originally predate the change to the primary
> plane code that calls .update_primary_plane() also when disabling the
> plane:
> 
>  commit fdd508a6419217cce28213f3c9bd27c02a0d4c71
>  Author: Ville Syrjälä <ville.syrjala at linux.intel.com>
>  Date:   Fri Aug 8 21:51:11 2014 +0300
> 
>     drm/i915: Call .update_primary_plane in intel_{enable,
>     disable}_primary_hw_plane()
> 
> v2: Warn but don't blow up when trying to enable a plane w/o an fb (Chris)
> 
> Cc: Sonika Jindal <sonika.jindal at intel.com>
> Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
Reviewed-by: Chris Wilson <chris at chris-wilson.co.uk>
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre