linux-yocto/drivers/gpu/drm/tiny
Hans de Goede 9b61db1aed drm: gm12u320: Do not take a mutex from a wait_event condition
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
2019-08-12 21:30:20 +02:00
..
gm12u320.c drm: gm12u320: Do not take a mutex from a wait_event condition 2019-08-12 21:30:20 +02:00
hx8357d.c
ili9225.c
ili9341.c
Kconfig
Makefile
mi0283qt.c
repaper.c
st7586.c
st7735r.c