[Intel-gfx] [PATCH 1/5] drm/i915/gt: One more flush for Baytrail clear residuals

[Mika Kuoppala]

Chris Wilson <chris at chris-wilson.co.uk> writes:

> Quoting Mika Kuoppala (2021-01-19 10:25:14)
>> Chris Wilson <chris at chris-wilson.co.uk> writes:
>> 
>> > CI reports that Baytail requires one more invalidate after CACHE_MODE
>> > for it to be happy.
>> >
>> > Fixes: ace44e13e577 ("drm/i915/gt: Clear CACHE_MODE prior to clearing residuals")
>> > Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
>> > Cc: Mika Kuoppala <mika.kuoppala at linux.intel.com>
>> > Cc: Akeem G Abodunrin <akeem.g.abodunrin at intel.com>
>> > ---
>> >  drivers/gpu/drm/i915/gt/gen7_renderclear.c | 9 ++++++---
>> >  1 file changed, 6 insertions(+), 3 deletions(-)
>> >
>> > diff --git a/drivers/gpu/drm/i915/gt/gen7_renderclear.c b/drivers/gpu/drm/i915/gt/gen7_renderclear.c
>> > index 39478712769f..8551e6de50e8 100644
>> > --- a/drivers/gpu/drm/i915/gt/gen7_renderclear.c
>> > +++ b/drivers/gpu/drm/i915/gt/gen7_renderclear.c
>> > @@ -353,19 +353,21 @@ static void gen7_emit_pipeline_flush(struct batch_chunk *batch)
>> >  
>> >  static void gen7_emit_pipeline_invalidate(struct batch_chunk *batch)
>> >  {
>> > -     u32 *cs = batch_alloc_items(batch, 0, 8);
>> > +     u32 *cs = batch_alloc_items(batch, 0, 10);
>> >  
>> >       /* ivb: Stall before STATE_CACHE_INVALIDATE */
>> > -     *cs++ = GFX_OP_PIPE_CONTROL(4);
>> > +     *cs++ = GFX_OP_PIPE_CONTROL(5);
>> >       *cs++ = PIPE_CONTROL_STALL_AT_SCOREBOARD |
>> >               PIPE_CONTROL_CS_STALL;
>> >       *cs++ = 0;
>> >       *cs++ = 0;
>> > +     *cs++ = 0;
>> 
>> dw[5] seems to be only for gen8+. Does it make a difference?
>
> Pipe-control has always supported a qword-write, so a packet-length of 4
> or 5 on gen4-7. As I recall the debate for gen8+ was whether
> pipe-control still supported only a dword-write, and so we went with
> always using the qword-length.

Yes, there seem to ample evidence that 5 is fine.

Reviewed-by: Mika Kuoppala <mika.kuoppala at linux.intel.com>

> -Chris