[PATCH] glx: Skip multisampled configs when matching pre-existing X visuals.

Chad Versace chad.versace at linux.intel.com
Fri Aug 3 10:48:38 PDT 2012

On 08/01/2012 10:43 PM, Ian Romanick wrote:
> On 07/31/2012 03:15 PM, Paul Berry wrote:
>> In __glXScreenInit() we generate the set of GLX visuals in two steps:
>> first we match each pre-existing X visual with a corresponding
>> FBConfig, then we generate a new X visual to correspond to all the
>> remaining FBConfigs.
>> The first step is used for the two default 24-bit visuals (true color
>> and direct color) and for the 32-bit visual.  If windowsystem
>> multisampling is enabled in Mesa, we need to ensure that none of these
>> three visuals gets matched to a multisampled config.
>> Fixes a bug with windowsystem multisampling in gnome-shell.  If the X
>> server happens to match up a multisampled FBConfig to the 32-bit
>> visual, gnome-shell will try to use it to read pixels from
>> alpha-blended windows (such as gnome-terminal), resulting in no window
>> appearing on screen.

I assisted in debugging the gnome-shell failure, and this patch looks like the
correct fix.

Reviewed-by: Chad Versace <chad.versace at linux.intel.com>

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