[Mesa-dev] [PATCH 10/17] gallium/util: Ensure util_framebuffer_get_num_samples() is valid

[eocallaghan at alterapraxis.com]

On 2016-03-25 14:20, Ilia Mirkin wrote:
> Instead of introducing buggy code in patch 6/17 and then fixing it up
> here, you need to fold this with patch 6 so that it's all done at the
> same time.

Yea, can do. Cheers,

> 
> On Thu, Mar 24, 2016 at 8:11 PM, Edward O'Callaghan
> <eocallaghan at alterapraxis.com> wrote:
>> Upon context creation, internal driver structures are malloc()'ed
>> and memset() to zero them. This results in a invalid number of
>> samples 'by default'. Handle this in the simplest way to avoid
>> elaborate and probably equally sub-optimial solutions.
>> 
>> V2: Minor, use "NOTE:" instead of "N.B." in comment.
>> 
>> Signed-off-by: Edward O'Callaghan <eocallaghan at alterapraxis.com>
>> Reviewed-by: Marek Olšák <marek.olsak at amd.com>
>> ---
>>  src/gallium/auxiliary/util/u_framebuffer.c | 8 +++++++-
>>  1 file changed, 7 insertions(+), 1 deletion(-)
>> 
>> diff --git a/src/gallium/auxiliary/util/u_framebuffer.c 
>> b/src/gallium/auxiliary/util/u_framebuffer.c
>> index 775f050..b020f27 100644
>> --- a/src/gallium/auxiliary/util/u_framebuffer.c
>> +++ b/src/gallium/auxiliary/util/u_framebuffer.c
>> @@ -204,9 +204,15 @@ util_framebuffer_get_num_samples(const struct 
>> pipe_framebuffer_state *fb)
>>      * In the case of ARB_framebuffer_no_attachment
>>      * we obtain the number of samples directly from
>>      * the framebuffer state.
>> +    *
>> +    * NOTE: fb->samples may wind up as zero due to memset()'s on 
>> internal
>> +    *       driver structures on their initialization and so we take 
>> the
>> +    *       MAX here to ensure we have a valid number of samples. 
>> However,
>> +    *       if samples is legitimately not getting set somewhere
>> +    *       multi-sampling will evidently break.
>>      */
>>     if (!(fb->nr_cbufs || fb->zsbuf))
>> -      return fb->samples;
>> +      return MAX2(fb->samples, 1);
>> 
>>     for (i = 0; i < fb->nr_cbufs; i++) {
>>        if (fb->cbufs[i]) {
>> --
>> 2.5.5
>> 
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