Patch "drm: bridge: dw-hdmi: Avoid resetting force in the detect function" has been added to the 5.9-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

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

to the 5.9-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     drm-bridge-dw-hdmi-avoid-resetting-force-in-the-dete.patch
and it can be found in the queue-5.9 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit ff84b4ca993f16965a929401586ca16633227510
Author: Jonathan Liu <net147@xxxxxxxxx>
Date:   Sat Oct 31 19:17:47 2020 +1100

    drm: bridge: dw-hdmi: Avoid resetting force in the detect function
    
    [ Upstream commit bc551d776b691022f49b5bb5379bd58f7c4eb76a ]
    
    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: 381f05a7a842 ("drm: bridge/dw_hdmi: add connector mode forcing")
    Signed-off-by: Jonathan Liu <net147@xxxxxxxxx>
    Reviewed-by: Sam Ravnborg <sam@xxxxxxxxxxxx>
    Signed-off-by: Sam Ravnborg <sam@xxxxxxxxxxxx>
    Link: https://patchwork.freedesktop.org/patch/msgid/20201031081747.372599-1-net147@xxxxxxxxx
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
index 748df1cacd2b7..0c79a9ba48bb6 100644
--- a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
+++ b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
@@ -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);