On Monday, October 29, 2018 10:19:54 AM PDT Rafael Antognolli wrote:
> Gen9 hardware requires some workarounds to disable preemption depending
> on the type of primitive being emitted.
>
> We implement this by adding a new atom that tracks BRW_NEW_PRIMITIVE.
> Whenever it happens, we check the current type of primitive and
> enable/disable object preemption.
>
> For now, we just ignore blorp. The only primitive it emits is
> 3DPRIM_RECTLIST, and since it's not listed in the workarounds, we can
> safely leave preemption enabled when it happens. Or it will be disabled
> by a previous 3DPRIMITIVE, which should be fine too.
>
> Signed-off-by: Rafael Antognolli <rafael.antogno...@intel.com>
> Cc: Kenneth Graunke <kenn...@whitecape.org>
> ---
> src/mesa/drivers/dri/i965/genX_state_upload.c | 47 +++++++++++++++++++
> 1 file changed, 47 insertions(+)
>
> diff --git a/src/mesa/drivers/dri/i965/genX_state_upload.c
> b/src/mesa/drivers/dri/i965/genX_state_upload.c
> index 740cb0c4d2e..3a01bab1ae1 100644
> --- a/src/mesa/drivers/dri/i965/genX_state_upload.c
> +++ b/src/mesa/drivers/dri/i965/genX_state_upload.c
> @@ -5563,6 +5563,50 @@ static const struct brw_tracked_state
> genX(blend_constant_color) = {
>
> /* ---------------------------------------------------------------------- */
>
> +#if GEN_GEN == 9
> +
> +/**
* Enable or disable preemption based on the current primitive type.
* (This should only be necessary on Gen9 hardware, not Gen10+.)
*
> + * Implement workarounds for preemption:
> + * - WaDisableMidObjectPreemptionForGSLineStripAdj
> + * - WaDisableMidObjectPreemptionForTrifanOrPolygon
> + */
> +static void
> +gen9_emit_preempt_wa(struct brw_context *brw)
> +{
I think this might be a bit easier to follow as
bool object_preemption = true;
if (brw->primitive == _3DPRIM_LINESTRIP_ADJ && brw->gs.enabled)
object_preemption = false;
if (brw->primitive == _3DPRIM_TRIFAN)
object_preemption = false;
brw_enable_obj_preemption(brw, object_preemption);
(with the comments of course.)
Do we need any stalling when whacking CS_CHICKEN1...?
Looking through the workarounds list, I believe that we also need to
disable mid-object preemption for _3DPRIM_LINELOOP (Gen9 WA #0816).
We may need to disable it if instance_count > 0 in the 3DPRIMITIVE
(Gen9 WA #0798).
We may also need to disable autostripping by whacking some chicken
registers if it's enabled (Gen9 WA #0799). Which would be lame,
because that's likely a useful optimization. I guess we could disable
preemption for TRILIST and LINELIST as well to be safe.
And GPGPU preemption looks like a mile long list of workarounds,
so let's not try it on Gen9.
> + /* WaDisableMidObjectPreemptionForGSLineStripAdj
> + *
> + * WA: Disable mid-draw preemption when draw-call is a linestrip_adj
> and
> + * GS is enabled.
> + */
> + bool object_preemption =
> + !(brw->primitive == _3DPRIM_LINESTRIP_ADJ && brw->gs.enabled);
> +
> + /* WaDisableMidObjectPreemptionForTrifanOrPolygon
> + *
> + * TriFan miscompare in Execlist Preemption test. Cut index that is on
> a
> + * previous context. End the previous, the resume another context with
> a
> + * tri-fan or polygon, and the vertex count is corrupted. If we prempt
> + * again we will cause corruption.
> + *
> + * WA: Disable mid-draw preemption when draw-call has a tri-fan.
> + */
> + object_preemption =
> + object_preemption && !(brw->primitive == _3DPRIM_TRIFAN);
> +
> + brw_enable_obj_preemption(brw, object_preemption);
> +}
> +
> +static const struct brw_tracked_state gen9_preempt_wa = {
> + .dirty = {
> + .mesa = 0,
> + .brw = BRW_NEW_PRIMITIVE | BRW_NEW_GEOMETRY_PROGRAM,
> + },
> + .emit = gen9_emit_preempt_wa,
> +};
> +#endif
> +
> +/* ---------------------------------------------------------------------- */
> +
> void
> genX(init_atoms)(struct brw_context *brw)
> {
> @@ -5867,6 +5911,9 @@ genX(init_atoms)(struct brw_context *brw)
>
> &genX(cut_index),
> &gen8_pma_fix,
> +#if GEN_GEN == 9
> + &gen9_preempt_wa,
> +#endif
> };
> #endif
>
>
signature.asc
Description: This is a digitally signed message part.
_______________________________________________ mesa-dev mailing list mesa-dev@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/mesa-dev
