Re: [PATCH] drm/i915: Always recompute watermarks when distrust_bios_wm is set, v2.

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



Reviewed-by: Mahesh Kumar <mahesh1.kumar@xxxxxxxxx>


On Wednesday 31 May 2017 09:12 PM, Maarten Lankhorst wrote:
On some systems there can be a race condition in which no crtc state is
added to the first atomic commit. This results in all crtc's having a
null DDB allocation, causing a FIFO underrun on any update until the
first modeset.

Changes since v1:
- Do not take the connection_mutex, this is already done below.

Reported-by: Maarten Lankhorst <maarten.lankhorst@xxxxxxxxxxxxxxx>
Inspired-by: Mahesh Kumar <mahesh1.kumar@xxxxxxxxx>
Signed-off-by: Maarten Lankhorst <maarten.lankhorst@xxxxxxxxxxxxxxx>
Fixes: 98d39494d375 ("drm/i915/gen9: Compute DDB allocation at atomic
check time (v4)")
Cc: <stable@xxxxxxxxxxxxxxx> # v4.8+
Cc: Mahesh Kumar <mahesh1.kumar@xxxxxxxxx>
Cc: Matt Roper <matthew.d.roper@xxxxxxxxx>
---
  drivers/gpu/drm/i915/intel_pm.c | 9 +++++++++
  1 file changed, 9 insertions(+)

diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index 936eef1634c7..fce4bc5ccc99 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -4819,11 +4819,19 @@ skl_compute_wm(struct drm_atomic_state *state)
  	struct drm_crtc_state *cstate;
  	struct intel_atomic_state *intel_state = to_intel_atomic_state(state);
  	struct skl_wm_values *results = &intel_state->wm_results;
+	struct drm_device *dev = state->dev;
  	struct skl_pipe_wm *pipe_wm;
  	bool changed = false;
  	int ret, i;
/*
+	 * When we distrust bios wm we always need to recompute to set the
+	 * expected DDB allocations for each CRTC.
+	 */
+	if (to_i915(dev)->wm.distrust_bios_wm)
+		changed = true;
+
+	/*
  	 * If this transaction isn't actually touching any CRTC's, don't
  	 * bother with watermark calculation.  Note that if we pass this
  	 * test, we're guaranteed to hold at least one CRTC state mutex,
@@ -4833,6 +4841,7 @@ skl_compute_wm(struct drm_atomic_state *state)
  	 */
  	for_each_new_crtc_in_state(state, crtc, cstate, i)
  		changed = true;
+
  	if (!changed)
  		return 0;

_______________________________________________
Intel-gfx mailing list
Intel-gfx@xxxxxxxxxxxxxxxxxxxxx
https://lists.freedesktop.org/mailman/listinfo/intel-gfx




[Index of Archives]     [Linux USB Devel]     [Linux Audio Users]     [Yosemite News]     [Linux Kernel]     [Linux SCSI]
  Powered by Linux