[Intel-gfx] [PATCH] drm/i915/fbc: fix the check for already reserved fbc size

[Ben Widawsky]

On Thu, Feb 05, 2015 at 12:04:27PM +0200, Jani Nikula wrote:
> The check for previously reserved stolen space size for FBC in
> i915_gem_stolen_setup_compression() did not take the compression
> threshold into account. Fix this by storing and comparing to
> uncompressed size instead.
> 
> The bug has been introduced in
> 
> commit 5e59f7175f96550ede91f58d267d2b551cb6fbba
> Author: Ben Widawsky <benjamin.widawsky at intel.com>
> Date:   Mon Jun 30 10:41:24 2014 -0700
> 
>     drm/i915: Try harder to get FBC
> 
> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=88975
> Suggested-by: Chris Wilson <chris at chris-wilson.co.uk>
> Cc: Ben Widawsky <benjamin.widawsky at intel.com>
> Cc: stable at vger.kernel.org # 3.17+
> Signed-off-by: Jani Nikula <jani.nikula at intel.com>

I guess we can argue semantically about whether or not it was a bug. If I didn't
put the DRM_INFO there, everything would have continued to work and nobody would
have complained. I personally prefer keeping the size as the compressed size
like you did here: https://bugs.freedesktop.org/show_bug.cgi?id=88975#c1
but Chris already reviewed this so nuts to me.