Quoting Kuogee Hsieh (2021-07-28 14:30:54) > Currently at dp_pm_resume() is_connected state is decided base on hpd connection > status only. This will put is_connected in wrongly "true" state at the scenario > that dongle attached to DUT but without hmdi cable connecting to it. Fix this > problem by adding read sink count from dongle and decided is_connected state base > on both sink count and hpd connection status. > Please add a Fixes tag. > Signed-off-by: Kuogee Hsieh <khsieh@xxxxxxxxxxxxxx> > --- > drivers/gpu/drm/msm/dp/dp_display.c | 23 +++++++++++++++++++++-- > 1 file changed, 21 insertions(+), 2 deletions(-) > > diff --git a/drivers/gpu/drm/msm/dp/dp_display.c b/drivers/gpu/drm/msm/dp/dp_display.c > index 2b660e9..9bcb261 100644 > --- a/drivers/gpu/drm/msm/dp/dp_display.c > +++ b/drivers/gpu/drm/msm/dp/dp_display.c > @@ -1308,6 +1308,17 @@ static int dp_display_remove(struct platform_device *pdev) > return 0; > } > > +static int dp_get_sink_count(struct dp_display_private *dp) > +{ > + u8 sink_count; > + > + sink_count = drm_dp_read_sink_count(dp->aux); drm_dp_read_sink_count() returns an int, not a u8. Comparing a u8 to less than zero doesn't make any sense as it isn't signed. > + if (sink_count < 0) > + return 0; > + > + return sink_count; > +} We can drop this function and just have an int count in dp_pm_resume() that is compared to < 0 and then ignored. > + > static int dp_pm_resume(struct device *dev) > { > struct platform_device *pdev = to_platform_device(dev); > @@ -1327,14 +1338,22 @@ static int dp_pm_resume(struct device *dev) > > dp_catalog_ctrl_hpd_config(dp->catalog); > > - status = dp_catalog_link_is_connected(dp->catalog); > + /* > + * set sink to normal operation mode -- D0 > + * before dpcd read > + */ > + dp_link_psm_config(dp->link, &dp->panel->link_info, false); > > + if ((status = dp_catalog_link_is_connected(dp->catalog))) > + dp->link->sink_count = dp_get_sink_count(dp); Do we need to call drm_dp_read_sink_count_cap() as well? > + else > + dp->link->sink_count = 0; > /* > * can not declared display is connected unless > * HDMI cable is plugged in and sink_count of > * dongle become 1 > */ > - if (status && dp->link->sink_count) Is 'status' used anymore? If not, please remove it. > + if (dp->link->sink_count) > dp->dp_display.is_connected = true; > else > dp->dp_display.is_connected = false;