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Message-Id: <20180316152301.110599992@linuxfoundation.org>
Date: Fri, 16 Mar 2018 16:22:41 +0100
From: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To: linux-kernel@...r.kernel.org
Cc: Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
stable@...r.kernel.org, Alex Deucher <alexander.deucher@....com>,
Mike Lothian <mike@...eburn.co.uk>,
Lyude Paul <lyude@...hat.com>, Lukas Wunner <lukas@...ner.de>
Subject: [PATCH 4.4 09/63] drm/amdgpu: Fix deadlock on runtime suspend
4.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: Lukas Wunner <lukas@...ner.de>
commit aa0aad57909eb321746325951d66af88a83bc956 upstream.
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+: 27d4ee03078a: workqueue: Allow retrieval of current task's work struct
Cc: stable@...r.kernel.org # v4.2+: 25c058ccaf2e: drm: Allow determining if current task is output poll worker
Cc: Alex Deucher <alexander.deucher@....com>
Tested-by: Mike Lothian <mike@...eburn.co.uk>
Reviewed-by: Lyude Paul <lyude@...hat.com>
Signed-off-by: Lukas Wunner <lukas@...ner.de>
Link: https://patchwork.freedesktop.org/patch/msgid/4c9bf72aacae1eef062bd134cd112e0770a7f121.1518338789.git.lukas@wunner.de
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
drivers/gpu/drm/amd/amdgpu/amdgpu_connectors.c | 58 ++++++++++++++++---------
1 file changed, 38 insertions(+), 20 deletions(-)
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_connectors.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_connectors.c
@@ -739,9 +739,11 @@ amdgpu_connector_lvds_detect(struct drm_
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);
@@ -760,8 +762,12 @@ amdgpu_connector_lvds_detect(struct drm_
/* 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;
}
@@ -862,9 +868,11 @@ amdgpu_connector_vga_detect(struct drm_c
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)
@@ -918,8 +926,10 @@ amdgpu_connector_vga_detect(struct drm_c
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;
}
@@ -981,9 +991,11 @@ amdgpu_connector_dvi_detect(struct drm_c
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;
@@ -1108,8 +1120,10 @@ out:
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;
}
@@ -1351,9 +1365,11 @@ amdgpu_connector_dp_detect(struct drm_co
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;
@@ -1421,8 +1437,10 @@ amdgpu_connector_dp_detect(struct drm_co
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;
}
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