[RFC 44/44] drm/i915: Fake batch support for page flips

John.C.Harrison
2014-06-26T17:26:08Z

Any commands written to the ring without the scheduler's knowledge can get lost
during a pre-emption event. This checkin updates the page flip code to send the
ring commands via the scheduler's 'fake batch' interface. Thus the page flip is
kept safe from being clobbered.
---
drivers/gpu/drm/i915/intel_display.c | 84 ++++++++++++++++------------------
1 file changed, 40 insertions(+), 44 deletions(-)

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index fa1ffbb..8bbc5d3 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -9099,8 +9099,8 @@ static int intel_gen7_queue_flip(struct drm_device *dev,
uint32_t flags)
{
struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
- uint32_t plane_bit = 0;
- int len, ret;
+ uint32_t plane_bit = 0, sched_flags;
+ int ret;

switch (intel_crtc->plane) {
case PLANE_A:
@@ -9117,18 +9117,6 @@ static int intel_gen7_queue_flip(struct drm_device *dev,
return -ENODEV;
}

- len = 4;
- if (ring->id == RCS) {
- len += 6;
- /*
- * On Gen 8, SRM is now taking an extra dword to accommodate
- * 48bits addresses, and we need a NOOP for the batch size to
- * stay even.
- */
- if (IS_GEN8(dev))
- len += 2;
- }
-
/*
* BSpec MI_DISPLAY_FLIP for IVB:
* "The full packet must be contained within the same cache line."
@@ -9139,13 +9127,7 @@ static int intel_gen7_queue_flip(struct drm_device *dev,
* then do the cacheline alignment, and finally emit the
* MI_DISPLAY_FLIP.
*/
- ret = intel_ring_cacheline_align(ring);
- if (ret)
- return ret;
-
- ret = intel_ring_begin(ring, len);
- if (ret)
- return ret;
+ sched_flags = i915_ebp_sf_cacheline_align;

/* 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
@@ -9157,32 +9139,46 @@ static int intel_gen7_queue_flip(struct drm_device *dev,
* 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));
- if (IS_GEN8(dev))
- intel_ring_emit(ring, MI_STORE_REGISTER_MEM_GEN8(1) |
- MI_SRM_LRM_GLOBAL_GTT);
- else
- intel_ring_emit(ring, MI_STORE_REGISTER_MEM(1) |
- MI_SRM_LRM_GLOBAL_GTT);
- intel_ring_emit(ring, DERRMR);
- intel_ring_emit(ring, ring->scratch.gtt_offset + 256);
- if (IS_GEN8(dev)) {
- intel_ring_emit(ring, 0);
- intel_ring_emit(ring, MI_NOOP);
- }
- }
+ uint32_t cmds[] = {
+ MI_LOAD_REGISTER_IMM(1),
+ DERRMR,
+ ~(DERRMR_PIPEA_PRI_FLIP_DONE |
+ DERRMR_PIPEB_PRI_FLIP_DONE |
+ DERRMR_PIPEC_PRI_FLIP_DONE),
+ IS_GEN8(dev) ? (MI_STORE_REGISTER_MEM_GEN8(1) |
+ MI_SRM_LRM_GLOBAL_GTT) :
+ (MI_STORE_REGISTER_MEM(1) |
+ MI_SRM_LRM_GLOBAL_GTT),
+ DERRMR,
+ ring->scratch.gtt_offset + 256,
+// if (IS_GEN8(dev)) {
+ 0,
+ MI_NOOP,
+// }
+ MI_DISPLAY_FLIP_I915 | plane_bit,
+ fb->pitches[0] | obj->tiling_mode,
+ intel_crtc->unpin_work->gtt_offset,
+ MI_NOOP
+ };
+ uint32_t len = sizeof(cmds) / sizeof(*cmds);
+
+ ret = i915_scheduler_queue_nonbatch(ring, cmds, len, &obj, 1, sched_flags);
+ } else {
+ uint32_t cmds[] = {
+ MI_DISPLAY_FLIP_I915 | plane_bit,
+ fb->pitches[0] | obj->tiling_mode,
+ intel_crtc->unpin_work->gtt_offset,
+ MI_NOOP
+ };
+ uint32_t len = sizeof(cmds) / sizeof(*cmds);

- intel_ring_emit(ring, MI_DISPLAY_FLIP_I915 | plane_bit);
- intel_ring_emit(ring, (fb->pitches[0] | obj->tiling_mode));
- intel_ring_emit(ring, intel_crtc->unpin_work->gtt_offset);
- intel_ring_emit(ring, (MI_NOOP));
+ ret = i915_scheduler_queue_nonbatch(ring, cmds, len, &obj, 1, sched_flags);
+ }
+ if (ret)
+ return ret;

intel_mark_page_flip_active(intel_crtc);
- i915_add_request_wo_flush(ring);
+
return 0;
}

--
1.7.9.5