On Tue, 25 Aug 2015, Sivakumar Thulasimani <sivakumar.thulasimani@xxxxxxxxx> wrote:
> From: "Thulasimani,Sivakumar" <sivakumar.thulasimani@xxxxxxxxx>
>
> This patch reads sink_count dpcd always and removes its
> read operation based on values in downstream port dpcd. Also
> we should read it irrespective of current status of sink.
Having to write "also" in a commit message is a good hint to stop and
think about whether that should be a separate patch. Maybe it should be,
here too?
BR,
Jani.
>
> 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
>
> Signed-off-by: Sivakumar Thulasimani <sivakumar.thulasimani@xxxxxxxxx>
> ---
> drivers/gpu/drm/i915/intel_dp.c | 33 ++++++++++++++-------------------
> 1 file changed, 14 insertions(+), 19 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
> index 8a66a44..9e4e27d 100644
> --- a/drivers/gpu/drm/i915/intel_dp.c
> +++ b/drivers/gpu/drm/i915/intel_dp.c
> @@ -3898,6 +3898,7 @@ intel_dp_get_dpcd(struct intel_dp *intel_dp)
> struct drm_device *dev = dig_port->base.base.dev;
> struct drm_i915_private *dev_priv = dev->dev_private;
> uint8_t rev;
> + uint8_t reg;
>
> if (intel_dp_dpcd_read_wake(&intel_dp->aux, 0x000, intel_dp->dpcd,
> sizeof(intel_dp->dpcd)) < 0)
> @@ -3908,6 +3909,13 @@ 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,
> + ®, 1) < 0)
> + return false;
> +
> + if (!DP_GET_SINK_COUNT(reg))
> + return false;
> +
> /* Check if the panel supports PSR */
> memset(intel_dp->psr_dpcd, 0, sizeof(intel_dp->psr_dpcd));
> if (is_edp(intel_dp)) {
> @@ -4374,12 +4382,6 @@ intel_dp_check_link_status(struct intel_dp *intel_dp)
>
> WARN_ON(!drm_modeset_is_locked(&dev->mode_config.connection_mutex));
>
> - if (!intel_encoder->base.crtc)
> - return;
> -
> - if (!to_intel_crtc(intel_encoder->base.crtc)->active)
> - return;
> -
> /* Try to read receiver status if the link appears to be up */
> if (!intel_dp_get_link_status(intel_dp, link_status)) {
> return;
> @@ -4390,6 +4392,12 @@ intel_dp_check_link_status(struct intel_dp *intel_dp)
> return;
> }
>
> + if (!intel_encoder->base.crtc)
> + return;
> +
> + if (!to_intel_crtc(intel_encoder->base.crtc)->active)
> + return;
> +
> /* Try to read the source of the interrupt */
> if (intel_dp->dpcd[DP_DPCD_REV] >= 0x11 &&
> intel_dp_get_sink_irq(intel_dp, &sink_irq_vector)) {
> @@ -4427,19 +4435,6 @@ intel_dp_detect_dpcd(struct intel_dp *intel_dp)
> if (!(dpcd[DP_DOWNSTREAMPORT_PRESENT] & DP_DWN_STRM_PORT_PRESENT))
> return connector_status_connected;
>
> - /* 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;
> - }
> -
> /* If no HPD, poke DDC gently */
> if (drm_probe_ddc(&intel_dp->aux.ddc))
> return connector_status_connected;
> --
> 1.7.9.5
>
--
Jani Nikula, Intel Open Source Technology Center
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