[Mesa-dev] [PATCH 1/2] Fix __glXInitializeVisualConfigFromTags's handling of unrecognized fbconfig tags.

[Xavier Chantry]

On Sun, May 2, 2010 at 10:17 PM, Dave Airlie <airlied at gmail.com> wrote:
> On Mon, May 3, 2010 at 3:43 AM, Aaron Plattner <aplattner at nvidia.com> wrote:
>> On Sun, May 02, 2010 at 02:39:07AM -0700, Dave Airlie wrote:
>>> On Fri, Apr 23, 2010 at 2:30 AM, Aaron Plattner <aplattner at nvidia.com> wrote:
>>> > __glXInitializeVisualConfigFromTags doesn't skip the payload of unrecognized
>>> > tags.  Instead, it treats the value as if it were the next tag, which can happen
>>> > if the server's GLX extension is not Mesa's.  For example, this falls down when
>>> > NVIDIA sends a GLX_FLOAT_COMPONENTS_NV = 0 pair, causing
>>> > __glXInitializeVisualConfigFromTags to bail out early.
>>>
>>> I've had a regression reported on irc from papillon81 with GLX_USE_GL
>>> and OpenSceneGraph bisected to this.
>>
>> The spec is pretty clear about the attribute format for protocol:
>>
>> (for visuals)
>>
>>    The first 18 properties are ordered; the remaining properties consist of a
>>    property type and a property value.
>>
>> (for fbconfigs)
>>
>>    The properties consist of a property type and a property value.
>>
>> You use __glXInitializeVisualConfigFromTags in glXChooseVisual, don't you?
>> I think you need something like "fbconfig_style_tags && bp++;"  Or I guess
>> you could just hope that the server never sends GLX_USE_GL as a visual or
>> FBconfig property.
>>
>
> Oh good point, same handling as GL_RGBA then,
>
> This look better?
>
> Dave.
>

Ah there, that explains why flightgear just died with
Error: Not able to create requested visual.

Both patches seem to fix it, thanks !