This is a note to let you know that I've just added the patch titled
drm/i915: Always recompute watermarks when distrust_bios_wm is set, v2.
to the 4.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
drm-i915-always-recompute-watermarks-when-distrust_bios_wm-is-set-v2.patch
and it can be found in the queue-4.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 4e3aed844547f63614363a386de126e6304e55fb Mon Sep 17 00:00:00 2001
From: Maarten Lankhorst <maarten.lankhorst@xxxxxxxxxxxxxxx>
Date: Wed, 31 May 2017 17:42:36 +0200
Subject: drm/i915: Always recompute watermarks when distrust_bios_wm is set, v2.
From: Maarten Lankhorst <maarten.lankhorst@xxxxxxxxxxxxxxx>
commit 4e3aed844547f63614363a386de126e6304e55fb upstream.
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: Mahesh Kumar <mahesh1.kumar@xxxxxxxxx>
Cc: Matt Roper <matthew.d.roper@xxxxxxxxx>
Link: http://patchwork.freedesktop.org/patch/msgid/20170531154236.27180-1-maarten.lankhorst@xxxxxxxxxxxxxxx
Reviewed-by: Mahesh Kumar <mahesh1.kumar@xxxxxxxxx>
Reviewed-by: Matt Roper <matthew.d.roper@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
(cherry picked from commit 367d73d2806085bb507ab44c1f532640917fd5ca)
Signed-off-by: Jani Nikula <jani.nikula@xxxxxxxxx>
---
drivers/gpu/drm/i915/intel_pm.c | 9 +++++++++
1 file changed, 9 insertions(+)
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -4114,11 +4114,19 @@ skl_compute_wm(struct drm_atomic_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,
@@ -4128,6 +4136,7 @@ skl_compute_wm(struct drm_atomic_state *
*/
for_each_crtc_in_state(state, crtc, cstate, i)
changed = true;
+
if (!changed)
return 0;
Patches currently in stable-queue which might be from maarten.lankhorst@xxxxxxxxxxxxxxx are
queue-4.9/drm-i915-always-recompute-watermarks-when-distrust_bios_wm-is-set-v2.patch
queue-4.9/drm-i915-check-for-null-i915_vma-in-intel_unpin_fb_obj.patch