On 11 January 2012 11:44, Kenneth Graunke <kenn...@whitecape.org> wrote:
> The gen7_urb atom depends on CACHE_NEW_VS_PROG and CACHE_NEW_GS_PROG, > causing gen7_upload_urb() to be called when switching to a new VS > program. > > In addition to partitioning the URB space between the VS and GS, > gen7_upload_urb() also allocated space for VS and PS push constants. > Unfortunately, this meant that whenever CACHE_NEW_VS was flagged, we'd > reallocate the space for the PS push constants. This appears to trash > the PS push constants until the next 3DSTATE_CONSTANT_PS packet. > > Since our URB allocation for push constants is entirely static, it makes > sense to split it out into its own atom that only subscribes to > BRW_NEW_CONTEXT. This avoids reallocating the space and trashing > constants. > > Fixes a rendering artifact in Extreme Tuxracer, where instead of a snow > trail, you'd get a bright red streak (affectionately known as the > "bloody penguin bug"). > > This also explains why adding VS-related dirty bits to gen7_ps_state > made the problem disappear: it made 3DSTATE_CONSTANT_PS be emitted after > every 3DSTATE_PUSH_CONSTANT_ALLOC_PS packet. > > NOTE: This is a candidate for the 7.11 and 8.0 branches. > > Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=38868 > Signed-off-by: Kenneth Graunke <kenn...@whitecape.org> > Reviewed-by: Paul Berry <stereotype...@gmail.com>
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