Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> writes:
> We are required to reload the TLBs around ppgtt switches. However, we
> already do an unconditional TLB invalidate before every batch and a flush
> afterwards, so this condition is already satisfied without extra flushes
> around the LRI instructions.
>
> Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
> ---
> drivers/gpu/drm/i915/i915_gem_gtt.c | 17 -----------------
> 1 file changed, 17 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_gem_gtt.c b/drivers/gpu/drm/i915/i915_gem_gtt.c
> index 057239ab3f70..999f15455f48 100644
> --- a/drivers/gpu/drm/i915/i915_gem_gtt.c
> +++ b/drivers/gpu/drm/i915/i915_gem_gtt.c
> @@ -1431,13 +1431,8 @@ static int hsw_mm_switch(struct i915_hw_ppgtt *ppgtt,
> {
> struct intel_engine_cs *engine = req->engine;
> u32 *cs;
> - int ret;
>
> /* NB: TLBs must be flushed and invalidated before a switch */
> - ret = engine->emit_flush(req, EMIT_INVALIDATE | EMIT_FLUSH);
The pattern slightly changes as you dont get the flush on the first
switch.
But what is there to flush on first switch anyways.
Reviewed-by: Mika Kuoppala <mika.kuoppala@xxxxxxxxx>
> - if (ret)
> - return ret;
> -
> cs = intel_ring_begin(req, 6);
> if (IS_ERR(cs))
> return PTR_ERR(cs);
> @@ -1458,13 +1453,8 @@ static int gen7_mm_switch(struct i915_hw_ppgtt *ppgtt,
> {
> struct intel_engine_cs *engine = req->engine;
> u32 *cs;
> - int ret;
>
> /* NB: TLBs must be flushed and invalidated before a switch */
> - ret = engine->emit_flush(req, EMIT_INVALIDATE | EMIT_FLUSH);
> - if (ret)
> - return ret;
> -
> cs = intel_ring_begin(req, 6);
> if (IS_ERR(cs))
> return PTR_ERR(cs);
> @@ -1477,13 +1467,6 @@ static int gen7_mm_switch(struct i915_hw_ppgtt *ppgtt,
> *cs++ = MI_NOOP;
> intel_ring_advance(req, cs);
>
> - /* XXX: RCS is the only one to auto invalidate the TLBs? */
> - if (engine->id != RCS) {
> - ret = engine->emit_flush(req, EMIT_INVALIDATE | EMIT_FLUSH);
> - if (ret)
> - return ret;
> - }
> -
> return 0;
> }
>
> --
> 2.11.0
>
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