This is a note to let you know that I've just added the patch titled
drm/amdgpu: Fix deadlock on runtime suspend
to the 4.4-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...
The filename of the patch is: drm-amdgpu-fix-deadlock-on-runtime-suspend.patch and it can be found in the queue-4.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.
From aa0aad57909eb321746325951d66af88a83bc956 Mon Sep 17 00:00:00 2001
From: Lukas Wunner lukas@wunner.de Date: Sun, 11 Feb 2018 10:38:28 +0100 Subject: drm/amdgpu: Fix deadlock on runtime suspend
From: Lukas Wunner lukas@wunner.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@vger.kernel.org # v4.2+: 27d4ee03078a: workqueue: Allow retrieval of current task's work struct Cc: stable@vger.kernel.org # v4.2+: 25c058ccaf2e: drm: Allow determining if current task is output poll worker Cc: Alex Deucher alexander.deucher@amd.com Tested-by: Mike Lothian mike@fireburn.co.uk Reviewed-by: Lyude Paul lyude@redhat.com Signed-off-by: Lukas Wunner lukas@wunner.de Link: https://patchwork.freedesktop.org/patch/msgid/4c9bf72aacae1eef062bd134cd112e... Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.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; }
Patches currently in stable-queue which might be from lukas@wunner.de are
queue-4.4/workqueue-allow-retrieval-of-current-task-s-work-struct.patch queue-4.4/drm-radeon-fix-deadlock-on-runtime-suspend.patch queue-4.4/drm-amdgpu-fix-deadlock-on-runtime-suspend.patch queue-4.4/drm-allow-determining-if-current-task-is-output-poll-worker.patch queue-4.4/drm-nouveau-fix-deadlock-on-runtime-suspend.patch