Re: [PATCH] drm/bridge: replace use of system_wq with system_percpu_wq

From: Thomas Zimmermann

Date: Mon Apr 27 2026 - 07:22:26 EST




Am 04.11.25 um 12:13 schrieb Marco Crivellari:
Currently if a user enqueue a work item using schedule_delayed_work() the
used wq is "system_wq" (per-cpu wq) while queue_delayed_work() use
WORK_CPU_UNBOUND (used when a cpu is not specified). The same applies to
schedule_work() that is using system_wq and queue_work(), that makes use
again of WORK_CPU_UNBOUND.

This lack of consistentcy cannot be addressed without refactoring the API.

This patch continues the effort to refactor worqueue APIs, which has begun
with the change introducing new workqueues and a new alloc_workqueue flag:

commit 128ea9f6ccfb ("workqueue: Add system_percpu_wq and system_dfl_wq")
commit 930c2ea566af ("workqueue: Add new WQ_PERCPU flag")

system_wq should be the per-cpu workqueue, yet in this name nothing makes
that clear, so replace system_wq with system_percpu_wq.

The old wq (system_wq) will be kept for a few release cycles.

Suggested-by: Tejun Heo <tj@xxxxxxxxxx>
Signed-off-by: Marco Crivellari <marco.crivellari@xxxxxxxx>

Reviewed-by: Thomas Zimmermann <tzimmermann@xxxxxxx>

---
drivers/gpu/drm/bridge/ite-it6505.c | 2 +-
drivers/gpu/drm/bridge/ti-tfp410.c | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/bridge/ite-it6505.c b/drivers/gpu/drm/bridge/ite-it6505.c
index a094803ba7aa..37bb8123cf9b 100644
--- a/drivers/gpu/drm/bridge/ite-it6505.c
+++ b/drivers/gpu/drm/bridge/ite-it6505.c
@@ -2048,7 +2048,7 @@ static void it6505_start_hdcp(struct it6505 *it6505)
DRM_DEV_DEBUG_DRIVER(dev, "start");
it6505_reset_hdcp(it6505);
- queue_delayed_work(system_wq, &it6505->hdcp_work,
+ queue_delayed_work(system_percpu_wq, &it6505->hdcp_work,
msecs_to_jiffies(2400));
}
diff --git a/drivers/gpu/drm/bridge/ti-tfp410.c b/drivers/gpu/drm/bridge/ti-tfp410.c
index b80ee089f880..85fa3f8a747e 100644
--- a/drivers/gpu/drm/bridge/ti-tfp410.c
+++ b/drivers/gpu/drm/bridge/ti-tfp410.c
@@ -115,7 +115,7 @@ static void tfp410_hpd_callback(void *arg, enum drm_connector_status status)
{
struct tfp410 *dvi = arg;
- mod_delayed_work(system_wq, &dvi->hpd_work,
+ mod_delayed_work(system_percpu_wq, &dvi->hpd_work,
msecs_to_jiffies(HOTPLUG_DEBOUNCE_MS));
}

--
--
Thomas Zimmermann
Graphics Driver Developer
SUSE Software Solutions Germany GmbH
Frankenstr. 146, 90461 Nürnberg, Germany, www.suse.com
GF: Jochen Jaser, Andrew McDonald, Werner Knoblich, (HRB 36809, AG Nürnberg)