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Message-Id: <4c9bf72aacae1eef062bd134cd112e0770a7f121.1518338789.git.lukas@wunner.de>
Date: Sun, 11 Feb 2018 10:38:28 +0100
From: Lukas Wunner <lukas@...ner.de>
To: Tejun Heo <tj@...nel.org>, Lai Jiangshan <jiangshanlai@...il.com>,
Alex Deucher <alexander.deucher@....com>,
Dave Airlie <airlied@...hat.com>,
Ben Skeggs <bskeggs@...hat.com>
Cc: dri-devel@...ts.freedesktop.org, Peter Wu <peter@...ensteyn.nl>,
nouveau@...ts.freedesktop.org, Lyude Paul <lyude@...hat.com>,
Hans de Goede <hdegoede@...hat.com>,
Pierre Moreau <pierre.morrow@...e.fr>,
linux-kernel@...r.kernel.org,
Ismo Toijala <ismo.toijala@...il.com>,
intel-gfx@...ts.freedesktop.org, Liviu Dudau <Liviu.Dudau@....com>,
Archit Taneja <architt@...eaurora.org>
Subject: [PATCH 5/5] drm/amdgpu: Fix deadlock on runtime suspend
amdgpu's ->runtime_suspend hook calls drm_kms_helper_poll_disable(),
which waits for the output poll worker to finish if it's running.
The output poll worker meanwhile calls pm_runtime_get_sync() in
amdgpu's ->detect hooks, which waits for the ongoing suspend to finish,
causing a deadlock.
Fix by not acquiring a runtime PM ref if the ->detect hooks are called
in the output poll worker's context. This is safe because the poll
worker is only enabled while runtime active and we know that
->runtime_suspend waits for it to finish.
Fixes: d38ceaf99ed0 ("drm/amdgpu: add core driver (v4)")
Cc: stable@...r.kernel.org # v4.2+: 1234567890ab: workqueue: Allow retrieval of current task's work struct
Cc: stable@...r.kernel.org # v4.2+: 1234567890ab: drm: Allow determining if current task is output poll worker
Cc: Alex Deucher <alexander.deucher@....com>
Signed-off-by: Lukas Wunner <lukas@...ner.de>
---
drivers/gpu/drm/amd/amdgpu/amdgpu_connectors.c | 58 +++++++++++++++++---------
1 file changed, 38 insertions(+), 20 deletions(-)
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_connectors.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_connectors.c
index 8ca3783f2deb..74d2efaec52f 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_connectors.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_connectors.c
@@ -736,9 +736,11 @@ amdgpu_connector_lvds_detect(struct drm_connector *connector, bool force)
enum drm_connector_status ret = connector_status_disconnected;
int r;
- r = pm_runtime_get_sync(connector->dev->dev);
- if (r < 0)
- return connector_status_disconnected;
+ if (!drm_kms_helper_is_poll_worker()) {
+ r = pm_runtime_get_sync(connector->dev->dev);
+ if (r < 0)
+ return connector_status_disconnected;
+ }
if (encoder) {
struct amdgpu_encoder *amdgpu_encoder = to_amdgpu_encoder(encoder);
@@ -757,8 +759,12 @@ amdgpu_connector_lvds_detect(struct drm_connector *connector, bool force)
/* check acpi lid status ??? */
amdgpu_connector_update_scratch_regs(connector, ret);
- pm_runtime_mark_last_busy(connector->dev->dev);
- pm_runtime_put_autosuspend(connector->dev->dev);
+
+ if (!drm_kms_helper_is_poll_worker()) {
+ pm_runtime_mark_last_busy(connector->dev->dev);
+ pm_runtime_put_autosuspend(connector->dev->dev);
+ }
+
return ret;
}
@@ -868,9 +874,11 @@ amdgpu_connector_vga_detect(struct drm_connector *connector, bool force)
enum drm_connector_status ret = connector_status_disconnected;
int r;
- r = pm_runtime_get_sync(connector->dev->dev);
- if (r < 0)
- return connector_status_disconnected;
+ if (!drm_kms_helper_is_poll_worker()) {
+ r = pm_runtime_get_sync(connector->dev->dev);
+ if (r < 0)
+ return connector_status_disconnected;
+ }
encoder = amdgpu_connector_best_single_encoder(connector);
if (!encoder)
@@ -924,8 +932,10 @@ amdgpu_connector_vga_detect(struct drm_connector *connector, bool force)
amdgpu_connector_update_scratch_regs(connector, ret);
out:
- pm_runtime_mark_last_busy(connector->dev->dev);
- pm_runtime_put_autosuspend(connector->dev->dev);
+ if (!drm_kms_helper_is_poll_worker()) {
+ pm_runtime_mark_last_busy(connector->dev->dev);
+ pm_runtime_put_autosuspend(connector->dev->dev);
+ }
return ret;
}
@@ -988,9 +998,11 @@ amdgpu_connector_dvi_detect(struct drm_connector *connector, bool force)
enum drm_connector_status ret = connector_status_disconnected;
bool dret = false, broken_edid = false;
- r = pm_runtime_get_sync(connector->dev->dev);
- if (r < 0)
- return connector_status_disconnected;
+ if (!drm_kms_helper_is_poll_worker()) {
+ r = pm_runtime_get_sync(connector->dev->dev);
+ if (r < 0)
+ return connector_status_disconnected;
+ }
if (!force && amdgpu_connector_check_hpd_status_unchanged(connector)) {
ret = connector->status;
@@ -1115,8 +1127,10 @@ amdgpu_connector_dvi_detect(struct drm_connector *connector, bool force)
amdgpu_connector_update_scratch_regs(connector, ret);
exit:
- pm_runtime_mark_last_busy(connector->dev->dev);
- pm_runtime_put_autosuspend(connector->dev->dev);
+ if (!drm_kms_helper_is_poll_worker()) {
+ pm_runtime_mark_last_busy(connector->dev->dev);
+ pm_runtime_put_autosuspend(connector->dev->dev);
+ }
return ret;
}
@@ -1359,9 +1373,11 @@ amdgpu_connector_dp_detect(struct drm_connector *connector, bool force)
struct drm_encoder *encoder = amdgpu_connector_best_single_encoder(connector);
int r;
- r = pm_runtime_get_sync(connector->dev->dev);
- if (r < 0)
- return connector_status_disconnected;
+ if (!drm_kms_helper_is_poll_worker()) {
+ r = pm_runtime_get_sync(connector->dev->dev);
+ if (r < 0)
+ return connector_status_disconnected;
+ }
if (!force && amdgpu_connector_check_hpd_status_unchanged(connector)) {
ret = connector->status;
@@ -1429,8 +1445,10 @@ amdgpu_connector_dp_detect(struct drm_connector *connector, bool force)
amdgpu_connector_update_scratch_regs(connector, ret);
out:
- pm_runtime_mark_last_busy(connector->dev->dev);
- pm_runtime_put_autosuspend(connector->dev->dev);
+ if (!drm_kms_helper_is_poll_worker()) {
+ pm_runtime_mark_last_busy(connector->dev->dev);
+ pm_runtime_put_autosuspend(connector->dev->dev);
+ }
return ret;
}
--
2.15.1
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