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authorChen-Yu Tsai <wens@csie.org>2020-06-29 14:00:32 +0800
committerMaxime Ripard <maxime@cerno.tech>2020-06-30 10:01:48 +0200
commitbda8eaa6dee7525f4dac950810a85a88bf6c2ba0 (patch)
treee7bb291d1405e515156a31ed70bd0093f19e4b7c /drivers
parent4ab59c3c638c6c8952bf07739805d20eb6358a4d (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 'drivers')
-rw-r--r--drivers/gpu/drm/sun4i/sun4i_hdmi_enc.c5
1 files changed, 2 insertions, 3 deletions
diff --git a/drivers/gpu/drm/sun4i/sun4i_hdmi_enc.c b/drivers/gpu/drm/sun4i/sun4i_hdmi_enc.c
index ce07ddc3e058..557cbe5ab35f 100644
--- a/drivers/gpu/drm/sun4i/sun4i_hdmi_enc.c
+++ b/drivers/gpu/drm/sun4i/sun4i_hdmi_enc.c
@@ -259,9 +259,8 @@ sun4i_hdmi_connector_detect(struct drm_connector *connector, bool force)
struct sun4i_hdmi *hdmi = drm_connector_to_sun4i_hdmi(connector);
unsigned long reg;
- if (readl_poll_timeout(hdmi->base + SUN4I_HDMI_HPD_REG, reg,
- reg & SUN4I_HDMI_HPD_HIGH,
- 0, 500000)) {
+ reg = readl(hdmi->base + SUN4I_HDMI_HPD_REG);
+ if (reg & SUN4I_HDMI_HPD_HIGH) {
cec_phys_addr_invalidate(hdmi->cec_adap);
return connector_status_disconnected;
}