[Mesa-dev] Doubt about Streamed Vertex Buffer Write message descriptor in SandyBridge

[Ilia Mirkin]

On Tue, Jul 22, 2014 at 11:25 AM, Samuel Iglesias Gonsálvez
<siglesias at igalia.com> wrote:
> Hello,
>
> I have a doubt related to Streamed Vertex Buffer Write message and its
> message descriptor in SandyBridge.
>
> Reading about Stream Output Primitives Written
> (snb_ihd_os_vol2_part1.pdf, pag 175), it says the following:
>
> "Whenever a GS thread outputs a DataPort Streamed Vertex Buffer Write
> (SVBWrite) message with the Increment Num Prims Written bit set, the
> SO_NUM_PRIMS_WRITTEN register will be incremented."
>
> According to SNB's spec [0], all the bits in the SVBWrite message
> descriptor are ignored and I have not found the definition of this bit
> in the documentation. Maybe I'm running the wrong pdfgrep command :-/
>
> After doing some Google searches, I found that in other doc [1] it's
> mentioned the "Increment Num Prims Written" bit inside the SVBWrite
> message descriptor is not ignored for SNB (at least, it doesn't say that
> explicitly).
>
> Do you know where is the "Increment Num Prims Written" bit defined in
> SNB's doc?

Not 100% sure if this is what you're looking for, but take a look at

https://01.org/linuxgraphics/sites/default/files/documentation/snb_ihd_os_vol4_part2.pdf

Page 23, 2.4.3.1 - SONumPrimsWritten and/or Page 29 - 2.4.4.1
NumGSPrimsGenerated and perhaps some of the other fields in the
FF_SYNC message.

Or wait until someone who knows what they're talking about replies :)

  -ilia

>
> Thanks,
>
> Sam
>
> [0] snb_ihd_os_vol4_part1.pdf, "3.9.11 Streamed Vertex Buffer Write
> [DevSNB]", page 260.
> [1] http://www.x.org/docs/intel/HD/IHD_OS_Vol_4_Part1_BJS.pdf "5.10.10
> Streamed Vertex Buffer Write [Pre-DevIVB]", page 247.
>
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