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| author | Chen-Yu Tsai <wens@csie.org> | 2020-06-29 14:00:32 +0800 |
|---|---|---|
| committer | Maxime Ripard <maxime@cerno.tech> | 2020-06-30 10:01:48 +0200 |
| commit | bda8eaa6dee7525f4dac950810a85a88bf6c2ba0 (patch) | |
| tree | e7bb291d1405e515156a31ed70bd0093f19e4b7c /arch/sh/kernel/ftrace.c | |
| parent | 4ab59c3c638c6c8952bf07739805d20eb6358a4d (diff) | |
drm: sun4i: hdmi: Remove extra HPD polling
The HPD sense mechanism in Allwinner's old HDMI encoder hardware is more
or less an input-only GPIO. Other GPIO-based HPD implementations
directly return the current state, instead of polling for a specific
state and returning the other if that times out.
Remove the I/O polling from sun4i_hdmi_connector_detect() and directly
return a known state based on the current reading. This also gets rid
of excessive CPU usage by kworker as reported on Stack Exchange [1] and
Armbian forums [2].
[1] https://superuser.com/questions/1515001/debian-10-buster-on-cubietruck-with-bug-in-sun4i-drm-hdmi
[2] https://forum.armbian.com/topic/14282-headless-systems-and-sun4i_drm_hdmi-a10a20/
Fixes: 9c5681011a0c ("drm/sun4i: Add HDMI support")
Signed-off-by: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Maxime Ripard <maxime@cerno.tech>
Link: https://patchwork.freedesktop.org/patch/msgid/20200629060032.24134-1-wens@kernel.org
Diffstat (limited to 'arch/sh/kernel/ftrace.c')
0 files changed, 0 insertions, 0 deletions