I think I mentioned something about the patch summary (the title) being too big before. The kernel documentation on submitting patches [1] says: "the "summary" must be no more than 70-75 characters". [1] https://www.kernel.org/doc/Documentation/SubmittingPatches Cheers, Ander On Wed, 2016-02-10 at 14:34 +0530, Shubhangi Shrivastava wrote: > This patch reads sink_count dpcd always and removes its > read operation based on values in downstream port dpcd. > > SINK_COUNT dpcd is not dependent on DOWNSTREAM_PORT_PRESENT dpcd. > SINK_COUNT denotes if a display is attached, while > DOWNSTREAM_PORT_PRESET indicates how many ports are available > in the dongle where display can be attached. so it is possible > for sink count to change irrespective of value in downstream > port dpcd. > > Here is a table of possible values and scenarios > > sink_count downstream_port > present > 0 0 no display is attached > 0 1 dongle is connected without display > 1 0 display connected directly > 1 1 display connected through dongle > > v2: Storing value of intel_dp->sink_count that is ready > for consumption. (Ander) > Squashing two commits into one. (Ander) > > v3: Added comment to explain the need of early return when > sink count is 0. (Ander) > > Tested-by: Nathan D Ciobanu <nathan.d.ciobanu@xxxxxxxxx> > Signed-off-by: Sivakumar Thulasimani <sivakumar.thulasimani@xxxxxxxxx> > Signed-off-by: Shubhangi Shrivastava <shubhangi.shrivastava@xxxxxxxxx> > Reviewed-by: Ander Conselvan de Oliveira <conselvan2@xxxxxxxxx> > --- > drivers/gpu/drm/i915/intel_dp.c | 30 +++++++++++++++++++++++------- > drivers/gpu/drm/i915/intel_drv.h | 1 + > 2 files changed, 24 insertions(+), 7 deletions(-) > > diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c > index 9fe78e1..a834c5f 100644 > --- a/drivers/gpu/drm/i915/intel_dp.c > +++ b/drivers/gpu/drm/i915/intel_dp.c > @@ -3862,6 +3862,27 @@ intel_dp_get_dpcd(struct intel_dp *intel_dp) > if (intel_dp->dpcd[DP_DPCD_REV] == 0) > return false; /* DPCD not present */ > > + if (intel_dp_dpcd_read_wake(&intel_dp->aux, DP_SINK_COUNT, > + &intel_dp->sink_count, 1) < 0) > + return false; > + > + /* > + * Sink count can change between short pulse hpd hence > + * a member variable in intel_dp will track any changes > + * between short pulse interrupts. > + */ > + intel_dp->sink_count = DP_GET_SINK_COUNT(intel_dp->sink_count); > + > + /* > + * SINK_COUNT == 0 and DOWNSTREAM_PORT_PRESENT == 1 implies that > + * a dongle is present but no display. Unless we require to know > + * if a dongle is present or not, we don't need to update > + * downstream port information. So, an early return here saves > + * time from performing other operations which are not required. > + */ > + if (!intel_dp->sink_count) > + return false; > + > /* Check if the panel supports PSR */ > memset(intel_dp->psr_dpcd, 0, sizeof(intel_dp->psr_dpcd)); > if (is_edp(intel_dp)) { > @@ -4379,14 +4400,9 @@ intel_dp_detect_dpcd(struct intel_dp *intel_dp) > /* If we're HPD-aware, SINK_COUNT changes dynamically */ > if (intel_dp->dpcd[DP_DPCD_REV] >= 0x11 && > intel_dp->downstream_ports[0] & DP_DS_PORT_HPD) { > - uint8_t reg; > - > - if (intel_dp_dpcd_read_wake(&intel_dp->aux, DP_SINK_COUNT, > - ®, 1) < 0) > - return connector_status_unknown; > > - return DP_GET_SINK_COUNT(reg) ? connector_status_connected > - : > connector_status_disconnected; > + return intel_dp->sink_count ? > + connector_status_connected : connector_status_disconnected; > } > > /* If no HPD, poke DDC gently */ > diff --git a/drivers/gpu/drm/i915/intel_drv.h > b/drivers/gpu/drm/i915/intel_drv.h > index 3d003d6..c04db07 100644 > --- a/drivers/gpu/drm/i915/intel_drv.h > +++ b/drivers/gpu/drm/i915/intel_drv.h > @@ -752,6 +752,7 @@ struct intel_dp { > uint32_t DP; > int link_rate; > uint8_t lane_count; > + uint8_t sink_count; > bool has_audio; > bool detect_done; > enum hdmi_force_audio force_audio; _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
