[Mesa-dev] [RFC] [PATCH 2/2] i965: setup the edge flag enable bit in VE on SNB+
eric at anholt.net
Thu Sep 8 08:39:46 PDT 2011
On Thu, 8 Sep 2011 11:00:52 +0800, Yuanhan Liu <yuanhan.liu at linux.intel.com> wrote:
> This patch is just for RFC, as I am not sure it's the right way to setup
> the edge flag enable bit in Vertex Element struture. Setting up this
> bit, according to Bspec, need do:
> 1. Edge flags are supported for the following primitives
> 2. This bit must only be ENABLED on the last valid VERTEX_ELEMENT
> 3. When set, Component 0 Control must be set to VFCOMP_STORE_SRC, and
> Component 1-3 Control must be set to VFCOMP_NOSTORE.
> 4. The Source Element Format must be set to the UINT format.
> This patch did 1, 2, but didn't do 3, 4. As it simply seems wrong to me
> just change the last vetex element's component setting and source
> element format.
> BTW, this patch fix the oglc pntrast fail on SNB(haven't tested it on
> IVB yet).
Could you include a piglit test for the failure?
> + /*
> + * According to Bspec, the edge flag enable bit should be set
> + * at the last valid vertex element structure
> + */
Instead of saying "According to the Bspec", could you actually cite the
text from the public PRM? For example, in one of my previous patches:
+ * And this last workaround is tricky because of the requirements on
+ * that bit. From section 220.127.116.11.3 "Stall" of the Sandy Bridge PRM
+ * volume 2 part 1:
+ * "1 of the following must also be set:
+ * - Render Target Cache Flush Enable ( of DW1)
+ * - Depth Cache Flush Enable ( of DW1)
+ * - Stall at Pixel Scoreboard ( of DW1)
+ * - Depth Stall ( of DW1)
+ * - Post-Sync Operation ( of DW1)
+ * - Notify Enable ( of DW1)"
It means that someone else stumbling on this code later gets a pointer
to where to start reading up on what's going on in the code.
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