[Mesa-dev] [PATCH 1/3] st/mesa: recreate sampler view on context change v2

[Brian Paul]

On 03/24/2014 10:04 AM, Christian König wrote:
> Am 24.03.2014 16:36, schrieb Brian Paul:
>> On 03/24/2014 08:06 AM, Christian König wrote:
>>> From: Christian König <christian.koenig at amd.com>
>>>
>>> With shared glx contexts it is possible that a texture is create and
>>> used
>>> in one context and then used in another one resulting in incorrect
>>> sampler view usage.
>>>
>>> v2: avoid template copy
>>>
>>> Signed-off-by: Christian König <christian.koenig at amd.com>
>>> Cc: "10.0 10.1" <mesa-stable at lists.freedesktop.org>
>>> ---
>>>   src/mesa/state_tracker/st_atom_texture.c | 7 +++++++
>>>   1 file changed, 7 insertions(+)
>>>
>>> diff --git a/src/mesa/state_tracker/st_atom_texture.c
>>> b/src/mesa/state_tracker/st_atom_texture.c
>>> index 3557a3f..dc7f635 100644
>>> --- a/src/mesa/state_tracker/st_atom_texture.c
>>> +++ b/src/mesa/state_tracker/st_atom_texture.c
>>> @@ -198,6 +198,13 @@ st_get_texture_sampler_view_from_stobj(struct
>>> st_texture_object *stObj,
>>>      if (!stObj->sampler_view) {
>>>         stObj->sampler_view =
>>>            st_create_texture_sampler_view_from_stobj(pipe, stObj,
>>> samp, format);
>>> +
>>> +   } else if (stObj->sampler_view->context != pipe) {
>>> +      /* Recreate view in correct context, use existing view as
>>> template */
>>> +      struct pipe_sampler_view *sv =
>>> +         pipe->create_sampler_view(pipe, stObj->pt,
>>> stObj->sampler_view);
>>> +      pipe_sampler_view_reference(&stObj->sampler_view, NULL);
>>> +      stObj->sampler_view = sv;
>>>      }
>>>
>>>      return stObj->sampler_view;
>>>
>>
>> My concern with this is if there really are multiple contexts using
>> one texture, we're going to continuously destroy and create sampler
>> views when we validate state.  Right?
>
> Yes that's correct and it also concerned me as well.
>
>>
>> Ultimately, the right solution might be to have a list of sampler
>> views per texture, one sampler view per context.  Since there usually
>> aren't too many contexts sharing textures, a linked list would
>> probably be OK.
>>
>
> Completely agree, but this patchset is meant to be a bugfix for the
> crashes we experience with 10.x. For master a solution with a linked
> list should work better indeed.

OK, let's put a 'XXX' comment describing that solution in the code for now.

With that, Reviewed-by: Brian Paul <brianp at vmware.com>


Will you try to implement the linked list?

-Brian