[Mesa-dev] [PATCH] intel: Emit assertion failure ASAP when DRI2 separate stencil handshake fails

[Chad Versace]

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On 08/19/2011 03:18 PM, Kenneth Graunke wrote:
> On 08/19/2011 10:44 AM, Chad Versace wrote:
>> On 08/19/2011 10:35 AM, Eric Anholt wrote:
>>> On Thu, 18 Aug 2011 14:02:46 -0700, Chad Versace <chad at chad-versace.us> wrote:
>>>> When intel_verify_dri2_has_hiz() discovers that DRI2 (that is, the DDX
>>>> driver) cannot provide a separate stencil buffer, but
>>>> intel_context::hw_must_use_separate_stencil is set, then emit an
>>>> informative assertion failure as soon as possible.
>>>>
>>>> Currently, we do emit an assertion failure, but the its location is
>>>> sufficiently unrelated to the DRI2 HiZ handshake as to be uninformative.
>>>> In experimenting with HiZ, Anholt encountered this assertion failure and
>>>> was unable to understand its cause.
>>>>
>>>> CC: Eric Anholt <eric at anholt.net>
>>>> Signed-off-by: Chad Versace <chad at chad-versace.us>
>>>> ---
>>>>  src/mesa/drivers/dri/intel/intel_context.c |    4 ++++
>>>>  1 files changed, 4 insertions(+), 0 deletions(-)
>>>>
>>>> diff --git a/src/mesa/drivers/dri/intel/intel_context.c b/src/mesa/drivers/dri/intel/intel_context.c
>>>> index fe8be08..b9d2579 100644
>>>> --- a/src/mesa/drivers/dri/intel/intel_context.c
>>>> +++ b/src/mesa/drivers/dri/intel/intel_context.c
>>>> @@ -1454,6 +1454,10 @@ intel_verify_dri2_has_hiz(struct intel_context *intel,
>>>>  	  * a combined depth/stencil buffer. Discard the hiz buffer too.
>>>>  	  */
>>>>  	 intel->intelScreen->dri2_has_hiz = INTEL_DRI2_HAS_HIZ_FALSE;
>>>> +	 if (intel->must_use_separate_stencil) {
>>>> +	    assert(!"intel_context requires separate stencil, but the "
>>>> +		    "DRIscreen does not support it");
>>>> +	 }
>>>>  
>>>
>>> If it's something we think people can actually hit (and in this case we
>>> do), just use _mesa_problem so people see it even if they aren't
>>> building with assertions.
>>
>> I would also like to throw an assertion immediately after _mesa_problem(), like below.
>> Since an assertion will eventually fail anyway, we might as well die ASAP.
>>
>> _mesa_probelm(ctx, "intel_context requires separate stencil, but the "
>>                    "DRIscreen does no support it. You may need to upgrade "
>>                    "the Intel X driver to 2.16.0");
>> assert(0);
> 
> Not assert(0)...abort().  assertions get compiled away to nothing in
> release mode.

Thanks. I have never used abort() before... I forgot it was in the toolbox.

If I replace the assert with abort, is everyone happy?

- -- 
Chad Versace
chad at chad-versace.us
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