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drm/amd/display: Use unbound workqueues for deferred DM work

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DM currently queues some deferred display work on system workqueues.
Low-context IRQ handlers are queued on system_highpri_wq, while deferred
vmin/vmax updates are queued on system_percpu_wq.

Both paths can execute long-running display work. HPD and HPD RX handling
may involve link detection, AUX transactions, connector state updates, and
hotplug notification. The vmin/vmax update path calls into DC under
dc_lock to adjust stream timing. These paths can therefore trigger the
workqueue CPU hog detector when run from per-CPU workers:

  workqueue: dm_irq_work_func [amdgpu] hogged CPU for >10000us
  workqueue: dm_handle_vmin_vmax_update [amdgpu] hogged CPU for >10000us

Move the deferred low-context IRQ work to a dedicated high-priority
unbound workqueue, preserving the priority of the previous
system_highpri_wq usage while avoiding long-running work on per-CPU
workers.

Move deferred vmin/vmax updates to a separate normal-priority unbound
workqueue.

High-context IRQ handlers remain unchanged and continue to run directly
from the IRQ path.

Signed-off-by: Geoffrey McRae <geoffrey.mcrae@amd.com>
Reviewed-by: Leo Li <sunpeng.li@amd.com>
Cc: Harry Wentland <harry.wentland@amd.com>
Cc: Leo Li <sunpeng.li@amd.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Christian König <christian.koenig@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
This commit is contained in:
Geoffrey McRae
2026-06-30 02:14:49 +10:00
committed by Alex Deucher
parent 9102b39fa9
commit 4a209ac674
2 changed files with 32 additions and 3 deletions
Download Patch File Download Diff File Expand all files Collapse all files

4
drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm.h
View File

@@ -324,6 +324,8 @@ struct hpd_rx_irq_offload_work {
* @ddev: DRM base driver structure
* @display_indexes_num: Max number of display streams supported
* @irq_handler_list_table_lock: Synchronizes access to IRQ tables
* @irq_wq: Dedicated high-priority unbound workqueue for deferred IRQ work
* @vmin_vmax_wq: Dedicated unbound workqueue for deferred vmin/vmax updates
* @backlight_dev: Backlight control device
* @backlight_link: Link on which to control backlight
* @backlight_caps: Capabilities of the backlight device
@@ -563,6 +565,8 @@ struct amdgpu_display_manager {
dmub_outbox_params[1];
spinlock_t irq_handler_list_table_lock;
struct workqueue_struct *irq_wq;
struct workqueue_struct *vmin_vmax_wq;
struct backlight_device *backlight_dev[AMDGPU_DM_MAX_NUM_EDP];

31
drivers/gpu/drm/amd/display/amdgpu_dm/amdgpu_dm_irq.c
View File

@@ -397,6 +397,21 @@ int amdgpu_dm_irq_init(struct amdgpu_device *adev)
spin_lock_init(&adev->dm.irq_handler_list_table_lock);
adev->dm.irq_wq = alloc_workqueue("amdgpu_dm_irq",
WQ_UNBOUND | WQ_HIGHPRI, 0);
if (!adev->dm.irq_wq)
return -ENOMEM;
adev->dm.vmin_vmax_wq = alloc_workqueue("amdgpu_dm_vmin_vmax",
WQ_UNBOUND, 0);
if (!adev->dm.vmin_vmax_wq) {
destroy_workqueue(adev->dm.irq_wq);
adev->dm.irq_wq = NULL;
return -ENOMEM;
}
for (src = 0; src < DAL_IRQ_SOURCES_NUMBER; src++) {
/* low context handler list init */
lh = &adev->dm.irq_handler_list_low_tab[src];
@@ -478,6 +493,16 @@ void amdgpu_dm_irq_fini(struct amdgpu_device *adev)
list_del(&handler->list);
kfree(handler);
}
if (adev->dm.vmin_vmax_wq) {
destroy_workqueue(adev->dm.vmin_vmax_wq);
adev->dm.vmin_vmax_wq = NULL;
}
if (adev->dm.irq_wq) {
destroy_workqueue(adev->dm.irq_wq);
adev->dm.irq_wq = NULL;
}
}
EXPORT_IF_KUNIT(amdgpu_dm_irq_fini);
@@ -597,7 +622,7 @@ STATIC_IFN_KUNIT void amdgpu_dm_irq_schedule_work(struct amdgpu_device *adev,
goto out_unlock;
list_for_each_entry(handler_data, handler_list, list) {
if (queue_work(system_highpri_wq, &handler_data->work)) {
if (queue_work(adev->dm.irq_wq, &handler_data->work)) {
work_queued = true;
break;
}
@@ -625,7 +650,7 @@ STATIC_IFN_KUNIT void amdgpu_dm_irq_schedule_work(struct amdgpu_device *adev,
INIT_WORK(&handler_data_add->work, dm_irq_work_func);
if (queue_work(system_highpri_wq, &handler_data_add->work))
if (queue_work(adev->dm.irq_wq, &handler_data_add->work))
DRM_DEBUG("Queued work for handling interrupt from "
"display for IRQ source %d\n",
irq_source);
@@ -1913,7 +1938,7 @@ static void schedule_dc_vmin_vmax(struct amdgpu_device *adev,
offload_work->stream = stream;
offload_work->adjust = adjust_copy;
queue_work(system_percpu_wq, &offload_work->work);
queue_work(adev->dm.vmin_vmax_wq, &offload_work->work);
}
STATIC_IFN_KUNIT void dm_vupdate_high_irq(void *interrupt_params)