Can you try the attached patch? Also, if you haven't already, can you
try running a DIAGNOSTIC/DEBUG/LOCKDEBUG kernel?
>From 025745d6f43aff21c88bc9e3b393ce146fc9af04 Mon Sep 17 00:00:00 2001
From: Taylor R Campbell <riastr...@netbsd.org>
Date: Sun, 26 Dec 2021 16:05:20 +0000
Subject: [PATCH] drm: Fix locking around accurate vblank counts.
- Make drm_crtc_accurate_vblank_count require the caller to hold the
event lock, rather than take it internally.
- Fix locking around drm_crtc_accurate_vblank_count and related
operations in amdgpu and nouveau interrupt handlers.
- Use drm_crtc_vblank_put_locked, not drm_crtc_vblank_put, when we
already hold the event lock.
---
.../dist/drm/amd/display/amdgpu_dm/amdgpu_dm.c | 2 +-
.../drm/amd/display/amdgpu_dm/amdgpu_dm_crc.c | 2 ++
sys/external/bsd/drm2/dist/drm/drm_vblank.c | 15 ++-------------
.../drm/nouveau/dispnv50/nouveau_dispnv50_disp.c | 2 +-
4 files changed, 6 insertions(+), 15 deletions(-)
diff --git a/sys/external/bsd/drm2/dist/drm/amd/display/amdgpu_dm/amdgpu_dm.c
b/sys/external/bsd/drm2/dist/drm/amd/display/amdgpu_dm/amdgpu_dm.c
index c8cbf7a6f68e..d0386f514457 100644
--- a/sys/external/bsd/drm2/dist/drm/amd/display/amdgpu_dm/amdgpu_dm.c
+++ b/sys/external/bsd/drm2/dist/drm/amd/display/amdgpu_dm/amdgpu_dm.c
@@ -361,7 +361,7 @@ static void dm_pflip_high_irq(void *interrupt_params)
drm_crtc_send_vblank_event(&amdgpu_crtc->base, e);
/* Event sent, so done with vblank for this flip */
- drm_crtc_vblank_put(&amdgpu_crtc->base);
+ drm_crtc_vblank_put_locked(&amdgpu_crtc->base);
}
} else if (e) {
/* VRR active and inside front-porch: vblank count and
diff --git
a/sys/external/bsd/drm2/dist/drm/amd/display/amdgpu_dm/amdgpu_dm_crc.c
b/sys/external/bsd/drm2/dist/drm/amd/display/amdgpu_dm/amdgpu_dm_crc.c
index 79cb94ea67dc..5a154037c524 100644
--- a/sys/external/bsd/drm2/dist/drm/amd/display/amdgpu_dm/amdgpu_dm_crc.c
+++ b/sys/external/bsd/drm2/dist/drm/amd/display/amdgpu_dm/amdgpu_dm_crc.c
@@ -319,7 +319,9 @@ void amdgpu_dm_crtc_handle_crc_irq(struct drm_crtc *crtc)
&crcs[0], &crcs[1], &crcs[2]))
return;
+ spin_lock(&crtc->dev->event_lock);
drm_crtc_add_crc_entry(crtc, true,
drm_crtc_accurate_vblank_count(crtc),
crcs);
+ spin_unlock(&crtc->dev->event_lock);
}
}
diff --git a/sys/external/bsd/drm2/dist/drm/drm_vblank.c
b/sys/external/bsd/drm2/dist/drm/drm_vblank.c
index 9ced81bd7ed8..ec91bbe9391b 100644
--- a/sys/external/bsd/drm2/dist/drm/drm_vblank.c
+++ b/sys/external/bsd/drm2/dist/drm/drm_vblank.c
@@ -337,7 +337,7 @@ static u64 drm_vblank_count(struct drm_device *dev,
unsigned int pipe)
* This is mostly useful for hardware that can obtain the scanout position, but
* doesn't have a hardware frame counter.
*/
-static u64 drm_crtc_accurate_vblank_count_locked(struct drm_crtc *crtc)
+u64 drm_crtc_accurate_vblank_count(struct drm_crtc *crtc)
{
struct drm_device *dev = crtc->dev;
unsigned int pipe = drm_crtc_index(crtc);
@@ -358,17 +358,6 @@ static u64 drm_crtc_accurate_vblank_count_locked(struct
drm_crtc *crtc)
return vblank;
}
-
-u64 drm_crtc_accurate_vblank_count(struct drm_crtc *crtc)
-{
- u64 vblank;
-
- spin_lock(&crtc->dev->event_lock);
- vblank = drm_crtc_accurate_vblank_count_locked(crtc);
- spin_unlock(&crtc->dev->event_lock);
-
- return vblank;
-}
EXPORT_SYMBOL(drm_crtc_accurate_vblank_count);
static void __disable_vblank(struct drm_device *dev, unsigned int pipe)
@@ -972,7 +961,7 @@ void drm_crtc_arm_vblank_event(struct drm_crtc *crtc,
assert_spin_locked(&dev->event_lock);
e->pipe = pipe;
- e->sequence = drm_crtc_accurate_vblank_count_locked(crtc) + 1;
+ e->sequence = drm_crtc_accurate_vblank_count(crtc) + 1;
list_add_tail(&e->base.link, &dev->vblank_event_list);
}
EXPORT_SYMBOL(drm_crtc_arm_vblank_event);
diff --git
a/sys/external/bsd/drm2/dist/drm/nouveau/dispnv50/nouveau_dispnv50_disp.c
b/sys/external/bsd/drm2/dist/drm/nouveau/dispnv50/nouveau_dispnv50_disp.c
index b9423cdc84fb..f49bb2ddf56d 100644
--- a/sys/external/bsd/drm2/dist/drm/nouveau/dispnv50/nouveau_dispnv50_disp.c
+++ b/sys/external/bsd/drm2/dist/drm/nouveau/dispnv50/nouveau_dispnv50_disp.c
@@ -2136,9 +2136,9 @@ nv50_disp_atomic_commit_tail(struct drm_atomic_state
*state)
if (new_crtc_state->event) {
unsigned long flags;
/* Get correct count/ts if racing with vblank irq */
+ spin_lock_irqsave(&crtc->dev->event_lock, flags);
if (new_crtc_state->active)
drm_crtc_accurate_vblank_count(crtc);
- spin_lock_irqsave(&crtc->dev->event_lock, flags);
drm_crtc_send_vblank_event(crtc, new_crtc_state->event);
spin_unlock_irqrestore(&crtc->dev->event_lock, flags);
