The ->preclose() hook is a good place to block for pending atomic
updates. We can't do this in ->postclose(), as it needs to happen
before drm_fb_release(). Otherwise, since we have already swapped
state (in the case of a non-blocking atomic update), this means that
the plane_state->fb will be released and cleared before we wait for
fences from the atomic-commit wq.
There are probably more complex solutions possible. But since already
scheduled atomic update, possibly blocking on already scheduled gpu/etc
fences, will complete eventually (assuming nothing catches fire), so
the sanest thing seems to be just block until already scheduled atomic
updates complete before tearing things down.
Fixes:
WARNING: CPU: 1 PID: 69 at ../drivers/gpu/drm/drm_atomic_helper.c:1061 drm_atomic_helper_wait_for_fences+0xe0/0xf8
Modules linked in:
CPU: 1 PID: 69 Comm: kworker/1:1 Tainted: G W 4.11.0-rc8+ #1187
Hardware name: Qualcomm Technologies, Inc. APQ 8016 SBC (DT)
Workqueue: events drm_mode_rmfb_work_fn
task: ffffffc036560d00 task.stack: ffffffc036550000
PC is at drm_atomic_helper_wait_for_fences+0xe0/0xf8
LR is at complete_commit.isra.1+0x44/0x1c0
pc : [<ffffff80084f6040>] lr : [<ffffff800854176c>] pstate: 20000145
sp : ffffffc036553b60
x29: ffffffc036553b60 x28: ffffffc0264e6a00
x27: ffffffc035659000 x26: 0000000000000000
x25: ffffffc0240e8000 x24: 0000000000000038
x23: 0000000000000000 x22: ffffff800858f200
x21: ffffffc0240e8000 x20: ffffffc02f56a800
x19: 0000000000000000 x18: 0000000000000000
x17: 0000000000000000 x16: 0000000000000000
x15: 0000000000000000 x14: ffffffc00a192700
x13: 0000000000000004 x12: 0000000000000000
x11: ffffff80089a1690 x10: 00000000000008f0
x9 : ffffffc036553b20 x8 : ffffffc036561650
x7 : ffffffc03fe6cb40 x6 : 0000000000000000
x5 : 0000000000000001 x4 : 0000000000000002
x3 : ffffffc035659000 x2 : ffffffc0240e8c80
x1 : 0000000000000000 x0 : ffffffc02adbe588
---[ end trace 13aeec77c3fb55e2 ]---
Call trace:
Exception stack(0xffffffc036553990 to 0xffffffc036553ac0)
3980: 0000000000000000 0000008000000000
39a0: ffffffc036553b60 ffffff80084f6040 0000000000004ff0 0000000000000038
39c0: ffffffc0365539d0 ffffff800857e098 ffffffc036553a00 ffffff800857e1b0
39e0: ffffffc036553a10 ffffff800857c554 ffffffc0365e8400 ffffffc0365e8400
3a00: ffffffc036553a20 ffffff8008103358 000000000001aad7 ffffff800851b72c
3a20: ffffffc036553a50 ffffff80080e9228 ffffffc02adbe588 0000000000000000
3a40: ffffffc0240e8c80 ffffffc035659000 0000000000000002 0000000000000001
3a60: 0000000000000000 ffffffc03fe6cb40 ffffffc036561650 ffffffc036553b20
3a80: 00000000000008f0 ffffff80089a1690 0000000000000000 0000000000000004
3aa0: ffffffc00a192700 0000000000000000 0000000000000000 0000000000000000
[<ffffff80084f6040>] drm_atomic_helper_wait_for_fences+0xe0/0xf8
[<ffffff800854176c>] complete_commit.isra.1+0x44/0x1c0
[<ffffff8008541c64>] msm_atomic_commit+0x32c/0x350
[<ffffff8008516230>] drm_atomic_commit+0x50/0x60
[<ffffff8008517548>] drm_atomic_remove_fb+0x158/0x250
[<ffffff80085186d0>] drm_framebuffer_remove+0x50/0x158
[<ffffff8008518818>] drm_mode_rmfb_work_fn+0x40/0x58
[<ffffff80080d5668>] process_one_work+0x1d0/0x378
[<ffffff80080d5a54>] worker_thread+0x244/0x488
[<ffffff80080db7fc>] kthread+0xfc/0x128
[<ffffff8008082ec0>] ret_from_fork+0x10/0x50
Reported-by: Stanimir Varbanov <stanimir.varbanov@xxxxxxxxxx>
Signed-off-by: Rob Clark <robdclark@xxxxxxxxx>
---
The hunk that removes the comment about ->preclose() included in this
patch to challenge the assumption that ->preclose() shouldn't exist ;-)
drivers/gpu/drm/msm/msm_drv.c | 10 +++++++++-
include/drm/drm_drv.h | 3 ---
2 files changed, 9 insertions(+), 4 deletions(-)
diff --git a/drivers/gpu/drm/msm/msm_drv.c b/drivers/gpu/drm/msm/msm_drv.c
index 87b5695..c8763b9 100644
--- a/drivers/gpu/drm/msm/msm_drv.c
+++ b/drivers/gpu/drm/msm/msm_drv.c
@@ -540,6 +540,13 @@ static int msm_open(struct drm_device *dev, struct drm_file *file)
return 0;
}
+static void msm_preclose(struct drm_device *dev, struct drm_file *file)
+{
+ struct msm_drm_private *priv = dev->dev_private;
+
+ flush_workqueue(priv->atomic_wq);
+}
+
static void msm_postclose(struct drm_device *dev, struct drm_file *file)
{
struct msm_drm_private *priv = dev->dev_private;
@@ -813,7 +820,8 @@ static struct drm_driver msm_driver = {
DRIVER_ATOMIC |
DRIVER_MODESET,
.open = msm_open,
- .postclose = msm_postclose,
+ .preclose = msm_preclose,
+ .postclose = msm_postclose,
.lastclose = msm_lastclose,
.irq_handler = msm_irq,
.irq_preinstall = msm_irq_preinstall,
diff --git a/include/drm/drm_drv.h b/include/drm/drm_drv.h
index 53b9832..a045ada 100644
--- a/include/drm/drm_drv.h
+++ b/include/drm/drm_drv.h
@@ -114,9 +114,6 @@ struct drm_driver {
* one &struct drm_file (see &drm_file.is_master and &drm_device.master)
* there should never be a need to tear down any modeset related
* resources in this callback. Doing so would be a driver design bug.
- *
- * FIXME: It is not really clear why there's both @preclose and
- * @postclose. Without a really good reason, use @postclose only.
*/
void (*preclose) (struct drm_device *, struct drm_file *file_priv);
--
2.9.3
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