Instead of having a work item that never stops (which really should be
a kthread), with a dedicated workqueue to not upset anyone else, use a
delayed work. A bunch of changes:
- We can throw out all the custom wakeup and requeue logic and state
tracking. If we schedule the work with a 0 delay it'll get
scheduled immediately.
- Persistent state (frame & draw_status_timeout) need to be moved out
of the work.
- diff is bigger than the changes, biggest chunk is reindenting the
work fn because it lost its while loop.
Lots of code deleting as consequence all over. Specifically we can
delete the drm_driver.release code now!
v2: Review from Hans:
- Use mod_delayed_work in the plane update path to make sure we do
actually schedule immediately). In the worker we still want
queue_delayed_work, which won't modify the timeout when the work is
already scheduled. Which is exactly what we want if the work races
with a plane update.
- Switch to system_long_wq, Hans says on usb2 a plane upload can take
80 ms.
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Cc: Hans de Goede <hdegoede@redhat.com>
Cc: "Noralf Trønnes" <noralf@tronnes.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20200323144950.3018436-46-daniel.vetter@ffwll.ch
I made the condition of the wait_event_timeout call in
gm12u320_fb_update_work a helper which takes a mutex to make sure
that any writes to fb_update.run or fb_update.fb from other CPU cores
are seen before the check is done.
This is not necessary as the wait_event helpers contain the necessary
barriers for this themselves.
More over it is harmfull since by the time the check is done the task
is no longer in the TASK_RUNNING state and calling mutex_lock while not
in task-running is not allowed, leading to this warning when the kernel
is build with some extra locking checks enabled:
[11947.450011] do not call blocking ops when !TASK_RUNNING; state=2 set at
[<00000000e4306de6>] prepare_to_wait_event+0x61/0x190
This commit fixes this by dropping the helper and simply directly
checking the condition (without unnecessary locking) in the
wait_event_timeout call.
Acked-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190811143725.5951-1-hdegoede@redhat.com
