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drm: bridge: dw-hdmi: Avoid resetting force in the detect function 

It has been observed that resetting force in the detect function can
result in the PHY being powered down in response to hot-plug detect
being asserted, even when the HDMI connector is forced on.

Enabling debug messages and adding a call to dump_stack() in
dw_hdmi_phy_power_off() shows the following in dmesg:
[  160.637413] dwhdmi-rockchip ff940000.hdmi: EVENT=plugin
[  160.637433] dwhdmi-rockchip ff940000.hdmi: PHY powered down in 0 iterations

Call trace:
dw_hdmi_phy_power_off
dw_hdmi_phy_disable
dw_hdmi_update_power
dw_hdmi_detect
dw_hdmi_connector_detect
drm_helper_probe_detect_ctx
drm_helper_hpd_irq_event
dw_hdmi_irq
irq_thread_fn
irq_thread
kthread
ret_from_fork

Fixes: 381f05a7a8 ("drm: bridge/dw_hdmi: add connector mode forcing")
Signed-off-by: Jonathan Liu <net147@gmail.com>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20201031081747.372599-1-net147@gmail.com
This commit is contained in:
Jonathan Liu 2020-10-31 19:17:47 +11:00 committed by Sam Ravnborg
parent a6c40b8032
commit bc551d776b
1 changed files with 0 additions and 6 deletions
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6
drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
View File

@ -2327,12 +2327,6 @@ static enum drm_connector_status dw_hdmi_detect(struct dw_hdmi *hdmi)
{
enum drm_connector_status result;
mutex_lock(&hdmi->mutex);
hdmi->force = DRM_FORCE_UNSPECIFIED;
dw_hdmi_update_power(hdmi);
dw_hdmi_update_phy_mask(hdmi);
mutex_unlock(&hdmi->mutex);
result = hdmi->phy.ops->read_hpd(hdmi, hdmi->phy.data);
mutex_lock(&hdmi->mutex);