[Intel-gfx] [PATCH 2/2] drm/i915: Use RCS flips on Ivybridge+
Stéphane Marchesin
marcheu at chromium.org
Thu Aug 29 19:11:53 CEST 2013
On Mon, Aug 26, 2013 at 1:43 PM, Stéphane Marchesin
<stephane.marchesin at gmail.com> wrote:
>
>
>
> On Mon, Aug 26, 2013 at 1:42 PM, Stéphane Marchesin
> <stephane.marchesin at gmail.com> wrote:
>>
>>
>>
>>
>> On Mon, Aug 26, 2013 at 12:58 PM, Chris Wilson <chris at chris-wilson.co.uk>
>> 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>
>>
>>
>> You can go ahead and say Tested-by, I ran my usual tests for 3 hours and
>> it didn't crash/show an issue. It would crash in ~10-30 minutes with the
>> other patches.
>
>
> Oh actually this one is a bit different... Give me 3 hours :)
>
Tested-by: Stéphane Marchesin <marcheu at chromium.org>
> Stéphane
>
>>
>>
>> Stéphane
>>
>>>
>>> Cc: Stephane Marchesin <marchesin at icps.u-strasbg.fr>
>>> Cc: Ben Widawsky <ben at bwidawsk.net>
>>> ---
>>> 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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