[Mesa-dev] [PATCH 2/6] mesa intel driver:

[Kenneth Graunke]

On 06/05/2012 01:12 PM, Ian Romanick wrote:
> On 06/05/2012 12:55 AM, Zhao, Halley wrote:
>> Thanks Paul, Thanks Ian as well for the comments on it.
>> I will update internal_format to GL_YCBCR_MESA.
>> (I didn't notice glext.h before, but gl2.h only)
>>
>> As to the error in intel_image_target_texture_2d(), it isn't caused by
>> wrong internal format, but hw limitation since we don't support packed
>> YUV as texture.
> 
> Yes and no.  The hardware natively supports the 422 subsampling, but
> GEN4 and later do not support the color space conversion.  For
> GL_YCBCR_MESA textures extra instructions are added after the texture
> lookup to perform the conversion.

But only in the old brw_wm_emit backend.  The new brw_fs backend broke
this, and nobody's bothered to fix it.