On Thu, 2017-10-26 at 22:41 +0300, Ville Syrjala wrote: > From: Ville Syrjälä <ville.syrj...@linux.intel.com> > > DP dongles may signal downstream HPD via short HPD pulses. Setting the > sink to DPMS off apparently kills the downstream HPD (at least on my > DP->VGA dongle), so skip the DPMS off for such dongles when we turn > off the port. > > Cc: David Woodhouse <dw...@infradead.org> > Cc: Imre Deak <imre.d...@intel.com> > Cc: Pablo <pablodebi...@nanalysis.com> > Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=103472 > Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=99114 > Signed-off-by: Ville Syrjälä <ville.syrj...@linux.intel.com> > --- > drivers/gpu/drm/i915/intel_dp.c | 18 +++++++++++++++++- > 1 file changed, 17 insertions(+), 1 deletion(-) > > diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c > index aa75f55eeb61..6ecc1b532f15 100644 > --- a/drivers/gpu/drm/i915/intel_dp.c > +++ b/drivers/gpu/drm/i915/intel_dp.c > @@ -2673,6 +2673,21 @@ static void intel_dp_get_config(struct intel_encoder > *encoder, > } > } > > +static bool downstream_hpd_needs_d0(struct intel_dp *intel_dp) > +{ > + /* > + * DPCD 1.2 should support BRANCH_DEVICE_CTRL, and thus > + * be capable of signalling downstream hpd with a long pulse. > + * Whether or not that means D3 is safe to use is not clear, > + * but let's assume so until proven otherwise. > + * > + * FIXME should really check all downstream ports... > + */ > + return intel_dp->dpcd[DP_DPCD_REV] == 0x11 && > + intel_dp->dpcd[DP_DOWNSTREAMPORT_PRESENT] & > DP_DWN_STRM_PORT_PRESENT && > + intel_dp->downstream_ports[0] & DP_DS_PORT_HPD; > +} > + > static void intel_disable_dp(struct intel_encoder *encoder, > const struct intel_crtc_state *old_crtc_state, > const struct drm_connector_state *old_conn_state) > @@ -2686,7 +2701,8 @@ static void intel_disable_dp(struct intel_encoder > *encoder,
It's not clear why the DDI counterpart is missing. > * ensure that we have vdd while we switch off the panel. */ > intel_edp_panel_vdd_on(intel_dp); > intel_edp_backlight_off(old_conn_state); > - intel_dp_sink_dpms(intel_dp, DRM_MODE_DPMS_OFF); > + if (!downstream_hpd_needs_d0(intel_dp)) > + intel_dp_sink_dpms(intel_dp, DRM_MODE_DPMS_OFF); > intel_edp_panel_off(intel_dp); > } > _______________________________________________ Intel-gfx mailing list Intel-gfx@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/intel-gfx
