On 03/30/2012 01:09 PM, Marcus Lorentzon wrote:
On 03/30/2012 12:12 PM, Ville Syrjälä wrote:
+#define DRM_FORMAT_NV12MT fourcc_code('T', 'M', '1', '2') /* 2x2 subsampled Cr:Cb plane 64x32 macroblocks */
This one is more difficult. Until now tiling was always handled in driver specific manner. OTOH if this format is really supported by different devices from multiple vendors, then it would probably make sense to add it as a standard format.
What about adding a DRM_FORMAT_PRIV_NV12MT and force vendor to add detailed documentation about this new format. Because if the format is not defined and documented, how will we ever discover if vendors have similar formats? And if we document all these MB formats "everyone" uses, then maybe we can get HW vendors to unify on a de facto standard. It would be nice to have an efficient format supported by everyone, instead of having to fallback to old linear formats every time you interact with another device.
Just for the record, documentation of this tiled macro-block format can be found here:
http://linuxtv.org/downloads/v4l-dvb-apis/re27.html
-- Regards, Sylwester