[Intel-gfx] [PATCH v2 01/18] drm/i915/lrc: Update PDPx registers with lri commands
Mika Kuoppala
mika.kuoppala at linux.intel.com
Thu Jun 11 11:04:15 PDT 2015
Michel Thierry <michel.thierry at intel.com> writes:
> A safer way to update the PDPx registers is sending lri commands, added
> in the ring before the batchbuffer start. Otherwise, the ctx must be idle
> before trying to change anything (but the ring-tail) in the ctx image. An
> example where the ctx won't be idle is lite-restore.
>
> This patch depends on [1], and has the advantage that it doesn't require
> to pre-allocate the top pdps like here [2].
>
> [1] http://mid.gmane.org/1432314314-23530-2-git-send-email-mika.kuoppala@intel.com
> [2] http://mid.gmane.org/1432314314-23530-3-git-send-email-mika.kuoppala@intel.com
>
> v2: Combine lri writes (and save 8 commands). (Mika)
>
> Cc: Dave Gordon <david.s.gordon at intel.com>
> Cc: Mika Kuoppala <mika.kuoppala at intel.com>
> Signed-off-by: Michel Thierry <michel.thierry at intel.com>
> ---
> drivers/gpu/drm/i915/intel_lrc.c | 43 ++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 43 insertions(+)
>
> diff --git a/drivers/gpu/drm/i915/intel_lrc.c b/drivers/gpu/drm/i915/intel_lrc.c
> index 626949a..51c0e06 100644
> --- a/drivers/gpu/drm/i915/intel_lrc.c
> +++ b/drivers/gpu/drm/i915/intel_lrc.c
> @@ -1116,13 +1116,56 @@ static int gen9_init_render_ring(struct intel_engine_cs *ring)
> return init_workarounds_ring(ring);
> }
>
> +static int intel_logical_ring_emit_pdps(struct intel_engine_cs *ring,
> + struct intel_context *ctx)
> +{
> + struct i915_hw_ppgtt *ppgtt = ctx->ppgtt;
> + struct intel_ringbuffer *ringbuf = ctx->engine[ring->id].ringbuf;
> + const int num_lri_cmds = GEN8_LEGACY_PDPES * 2;
> + int i, ret;
> +
> + ret = intel_logical_ring_begin(ringbuf, ctx, num_lri_cmds * 2 + 2);
> + if (ret)
> + return ret;
> +
> + intel_logical_ring_emit(ringbuf, MI_LOAD_REGISTER_IMM(num_lri_cmds));
> + for (i = GEN8_LEGACY_PDPES - 1; i >= 0; i--) {
> + const dma_addr_t pd_daddr = i915_page_dir_dma_addr(ppgtt, i);
> +
> + intel_logical_ring_emit(ringbuf, GEN8_RING_PDP_UDW(ring, i));
> + intel_logical_ring_emit(ringbuf, upper_32_bits(pd_daddr));
> + intel_logical_ring_emit(ringbuf, GEN8_RING_PDP_LDW(ring, i));
> + intel_logical_ring_emit(ringbuf, lower_32_bits(pd_daddr));
> + }
> +
> + intel_logical_ring_emit(ringbuf, MI_NOOP);
> + intel_logical_ring_advance(ringbuf);
> +
> + return 0;
> +}
> +
> static int gen8_emit_bb_start(struct intel_ringbuffer *ringbuf,
> struct intel_context *ctx,
> u64 offset, unsigned dispatch_flags)
> {
> + struct intel_engine_cs *ring = ringbuf->ring;
> bool ppgtt = !(dispatch_flags & I915_DISPATCH_SECURE);
> int ret;
>
> + /* Don't rely in hw updating PDPs, specially in lite-restore.
> + * Ideally, we should set Force PD Restore in ctx descriptor,
> + * but we can't. Force Restore would be a second option, but
> + * it is unsafe in case of lite-restore (because the ctx is
> + * not idle). */
> + if (ctx->ppgtt &&
Is this superfluous? Can the ctx->ppgtt ever be null with
execlists?
-Mika
> + (intel_ring_flag(ring) & ctx->ppgtt->pd_dirty_rings)) {
> + ret = intel_logical_ring_emit_pdps(ring, ctx);
> + if (ret)
> + return ret;
> +
> + ctx->ppgtt->pd_dirty_rings &= ~intel_ring_flag(ring);
> + }
> +
> ret = intel_logical_ring_begin(ringbuf, ctx, 4);
> if (ret)
> return ret;
> --
> 2.4.0
>
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