linux-uconsole/drivers/gpu
Chen-Yu Tsai 1788e4dde4 drm: sun4i: hdmi: Remove extra HPD polling
[ Upstream commit bda8eaa6de ]

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: 9c5681011a ("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
Signed-off-by: Sasha Levin <sashal@kernel.org>
2020-07-09 09:37:11 +02:00
..
drm drm: sun4i: hdmi: Remove extra HPD polling 2020-07-09 09:37:11 +02:00
host1x gpu: host1x: Allocate gather copy for host1x 2019-12-31 16:35:29 +01:00
ipu-v3 gpu: ipu-v3: pre: don't trigger update if buffer address doesn't change 2019-12-05 09:21:07 +01:00
vga vga_switcheroo: Fix missing gpu_bound call at audio client registration 2018-11-13 11:09:00 -08:00
Makefile