[Mesa-dev] [PATCH] i965: Disable unlit-centroid workaround on Gen < 6.

[Chris Forbes]

Possibly mark this for 10.4, since the assertion failures we hit when
emitting a pointless centroid workaround make other issues hard to
debug?

On Tue, Dec 9, 2014 at 8:44 PM, Chris Forbes <chrisf at ijw.co.nz> wrote:
> Reviewed-by: Chris Forbes <chrisf at ijw.co.nz>
>
> On Tue, Dec 9, 2014 at 8:08 PM, Matt Turner <mattst88 at gmail.com> wrote:
>> Back to the original commit (8313f444) adding the workaround, we were
>> enabling it on gens <= 7, even though gens <= 5 can't do multisampling.
>>
>> I cannot find documentation that says that Sandybridge needs this
>> workaround but in practice disabling it causes these piglit tests to
>> fail:
>>
>> EXT_framebuffer_multisample/interpolation {2,4} centroid-deriv{,-disabled}
>> ---
>>  src/mesa/drivers/dri/i965/brw_device_info.c | 3 ---
>>  1 file changed, 3 deletions(-)
>>
>> diff --git a/src/mesa/drivers/dri/i965/brw_device_info.c b/src/mesa/drivers/dri/i965/brw_device_info.c
>> index bbd907b..65942c2 100644
>> --- a/src/mesa/drivers/dri/i965/brw_device_info.c
>> +++ b/src/mesa/drivers/dri/i965/brw_device_info.c
>> @@ -28,7 +28,6 @@
>>  static const struct brw_device_info brw_device_info_i965 = {
>>     .gen = 4,
>>     .has_negative_rhw_bug = true,
>> -   .needs_unlit_centroid_workaround = true,
>>     .max_vs_threads = 16,
>>     .max_gs_threads = 2,
>>     .max_wm_threads = 8 * 4,
>> @@ -42,7 +41,6 @@ static const struct brw_device_info brw_device_info_g4x = {
>>     .has_pln = true,
>>     .has_compr4 = true,
>>     .has_surface_tile_offset = true,
>> -   .needs_unlit_centroid_workaround = true,
>>     .is_g4x = true,
>>     .max_vs_threads = 32,
>>     .max_gs_threads = 2,
>> @@ -57,7 +55,6 @@ static const struct brw_device_info brw_device_info_ilk = {
>>     .has_pln = true,
>>     .has_compr4 = true,
>>     .has_surface_tile_offset = true,
>> -   .needs_unlit_centroid_workaround = true,
>>     .max_vs_threads = 72,
>>     .max_gs_threads = 32,
>>     .max_wm_threads = 12 * 6,
>> --
>> 2.0.4
>>