Hi all,
This thread is about http://lists.freedesktop.org/archives/dri-devel/2013-April/037598.html.
We recently find some interesting thing about UVD based playback on loongson 3a plaform, and also find a way to fix the problem.
First, we find memcpy in [mesa]src/gallium/drivers/radeon/radeon_uvd.c caused the problem: * If memcpy is implemented though 16B or 8B load/store instructions, it will normally caused video mosaic. When insert a memcmp after the copying code in memcpy, it will report the src and dest are not equal. * If memcpy use 1B load/store instructions only, the memcmp after the copying code reports equal.
Then we find the following changeset fixs out problem:
diff --git a/src/gallium/drivers/radeon/radeon_uvd.c b/src/gallium/drivers/radeon/radeon_uvd.c index 2f98de2..f9599b6 100644 --- a/src/gallium/drivers/radeon/radeon_uvd.c +++ b/src/gallium/drivers/radeon/radeon_uvd.c @@ -162,7 +162,7 @@ static bool create_buffer(struct ruvd_decoder *dec, unsigned size) { buffer->buf = dec->ws->buffer_create(dec->ws, size, 4096, false, - RADEON_DOMAIN_GTT | RADEON_DOMAIN_VRAM); + RADEON_DOMAIN_GTT); if (!buffer->buf) return false;
The VRAM is mapped to an uncached area in out platform, so, my question is what could go wrong while using >4B load/store instructions in UVD workflow? Any idea?
-- Regards,
Chen Jie