[Intel-gfx] [PATCH 2/2] drm/i915: Use RCS flips on Ivybridge+
Daniel Vetter
daniel at ffwll.ch
Thu Aug 29 21:07:53 CEST 2013
On Mon, Aug 26, 2013 at 08:58:12PM +0100, Chris Wilson wrote:
> RCS flips do work on Iybridge+ so long as we can unmask the messages
> through DERRMR. However, there are quite a few workarounds mentioned
> regarding unmasking more than one event or triggering more than one
> message through DERRMR. Those workarounds in principle prevent us from
> performing pipelined flips (and asynchronous flips across multiple
> planes) and equally apply to the "known good" BCS ring. Given that it
> already appears to work, and also appears to work with unmasking all 3
> planes at once (and queuing flips across multiple planes), be brave.
>
> Bugzlla: https://bugs.freedesktop.org/show_bug.cgi?id=67600
> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> Lightly-tested-by: Stephane Marchesin <marchesin at icps.u-strasbg.fr>
> Cc: Stephane Marchesin <marchesin at icps.u-strasbg.fr>
> Cc: Ben Widawsky <ben at bwidawsk.net>
Both patches merged to dinq.
-Daniel
> ---
> drivers/gpu/drm/i915/i915_reg.h | 18 ++++++++++++++++
> drivers/gpu/drm/i915/intel_display.c | 40 ++++++++++++++++++++++++++++--------
> 2 files changed, 49 insertions(+), 9 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
> index c6f5009..df168f4 100644
> --- a/drivers/gpu/drm/i915/i915_reg.h
> +++ b/drivers/gpu/drm/i915/i915_reg.h
> @@ -230,6 +230,7 @@
> * address/value pairs. Don't overdue it, though, x <= 2^4 must hold!
> */
> #define MI_LOAD_REGISTER_IMM(x) MI_INSTR(0x22, 2*x-1)
> +#define MI_STORE_REGISTER_MEM(x) MI_INSTR(0x24, 2*x-1)
> #define MI_FLUSH_DW MI_INSTR(0x26, 1) /* for GEN6 */
> #define MI_FLUSH_DW_STORE_INDEX (1<<21)
> #define MI_INVALIDATE_TLB (1<<18)
> @@ -678,6 +679,23 @@
> #define FPGA_DBG_RM_NOCLAIM (1<<31)
>
> #define DERRMR 0x44050
> +#define DERRMR_PIPEA_SCANLINE (1<<0)
> +#define DERRMR_PIPEA_PRI_FLIP_DONE (1<<1)
> +#define DERRMR_PIPEA_SPR_FLIP_DONE (1<<2)
> +#define DERRMR_PIPEA_VBLANK (1<<3)
> +#define DERRMR_PIPEA_HBLANK (1<<5)
> +#define DERRMR_PIPEB_SCANLINE (1<<8)
> +#define DERRMR_PIPEB_PRI_FLIP_DONE (1<<9)
> +#define DERRMR_PIPEB_SPR_FLIP_DONE (1<<10)
> +#define DERRMR_PIPEB_VBLANK (1<<11)
> +#define DERRMR_PIPEB_HBLANK (1<<13)
> +/* Note that PIPEC is not a simple translation of PIPEA/PIPEB */
> +#define DERRMR_PIPEC_SCANLINE (1<<14)
> +#define DERRMR_PIPEC_PRI_FLIP_DONE (1<<15)
> +#define DERRMR_PIPEC_SPR_FLIP_DONE (1<<20)
> +#define DERRMR_PIPEC_VBLANK (1<<21)
> +#define DERRMR_PIPEC_HBLANK (1<<22)
> +
>
> /* GM45+ chicken bits -- debug workaround bits that may be required
> * for various sorts of correct behavior. The top 16 bits of each are
> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> index 9748dce..ffbcbd1 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -7826,12 +7826,6 @@ err:
> return ret;
> }
>
> -/*
> - * On gen7 we currently use the blit ring because (in early silicon at least)
> - * the render ring doesn't give us interrpts for page flip completion, which
> - * means clients will hang after the first flip is queued. Fortunately the
> - * blit ring generates interrupts properly, so use it instead.
> - */
> static int intel_gen7_queue_flip(struct drm_device *dev,
> struct drm_crtc *crtc,
> struct drm_framebuffer *fb,
> @@ -7839,9 +7833,13 @@ static int intel_gen7_queue_flip(struct drm_device *dev,
> {
> struct drm_i915_private *dev_priv = dev->dev_private;
> struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
> - struct intel_ring_buffer *ring = &dev_priv->ring[BCS];
> + struct intel_ring_buffer *ring;
> uint32_t plane_bit = 0;
> - int ret;
> + int len, ret;
> +
> + ring = obj->ring;
> + if (ring == NULL || ring->id != RCS)
> + ring = &dev_priv->ring[BCS];
>
> ret = intel_pin_and_fence_fb_obj(dev, obj, ring);
> if (ret)
> @@ -7863,10 +7861,34 @@ static int intel_gen7_queue_flip(struct drm_device *dev,
> goto err_unpin;
> }
>
> - ret = intel_ring_begin(ring, 4);
> + len = 4;
> + if (ring->id == RCS)
> + len += 6;
> +
> + ret = intel_ring_begin(ring, len);
> if (ret)
> goto err_unpin;
>
> + /* Unmask the flip-done completion message. Note that the bspec says that
> + * we should do this for both the BCS and RCS, and that we must not unmask
> + * more than one flip event at any time (or ensure that one flip message
> + * can be sent by waiting for flip-done prior to queueing new flips).
> + * Experimentation says that BCS works despite DERRMR masking all
> + * flip-done completion events and that unmasking all planes at once
> + * for the RCS also doesn't appear to drop events. Setting the DERRMR
> + * to zero does lead to lockups within MI_DISPLAY_FLIP.
> + */
> + if (ring->id == RCS) {
> + intel_ring_emit(ring, MI_LOAD_REGISTER_IMM(1));
> + intel_ring_emit(ring, DERRMR);
> + intel_ring_emit(ring, ~(DERRMR_PIPEA_PRI_FLIP_DONE |
> + DERRMR_PIPEB_PRI_FLIP_DONE |
> + DERRMR_PIPEC_PRI_FLIP_DONE));
> + intel_ring_emit(ring, MI_STORE_REGISTER_MEM(1));
> + intel_ring_emit(ring, DERRMR);
> + intel_ring_emit(ring, ring->scratch.gtt_offset + 256);
> + }
> +
> intel_ring_emit(ring, MI_DISPLAY_FLIP_I915 | plane_bit);
> intel_ring_emit(ring, (fb->pitches[0] | obj->tiling_mode));
> intel_ring_emit(ring, i915_gem_obj_ggtt_offset(obj) + intel_crtc->dspaddr_offset);
> --
> 1.8.4.rc3
>
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--
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch
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