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Commit 70ec0645 authored by Mika Kahola's avatar Mika Kahola Committed by Jani Nikula
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drm/i915: Check pixel rate for DP to VGA dongle 



Filter out a mode that exceeds the max pixel rate setting
for DP to VGA dongle. This is defined in DPCD register 0x81
if detailed cap info i.e. info field is 4 bytes long and
it is available for DP downstream port.

The register defines the pixel rate divided by 8 in MP/s.

v2: DPCD read outs and computation moved to drm (Ville, Daniel)
v3: Sink pixel rate computation moved to drm_dp_max_sink_dotclock()
    function (Daniel)
v4: Use of drm_dp_helper.c routines to compute max pixel clock (Ville)
v5: Use of intel_dp->downstream_ports to read out port capabilities.
    Code restructuring (Ville)
v6: Move DP branch device check to drm_dp_helper.c (Daniel)
v7: Cleanup as suggested by Ville

Reviewed-by: default avatarJim Bride <jim.bride@linux.intel.com>
Signed-off-by: default avatarMika Kahola <mika.kahola@intel.com>
Signed-off-by: default avatarJani Nikula <jani.nikula@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1473419458-17080-10-git-send-email-mika.kahola@intel.com
parent 1a2724fa

drivers/gpu/drm/i915/intel_dp.c

+26 −1
Original line number Diff line number Diff line
@@ -190,6 +190,29 @@ intel_dp_max_data_rate(int max_link_clock, int max_lanes) 
	return (max_link_clock * max_lanes * 8) / 10;

}



static int

intel_dp_downstream_max_dotclock(struct intel_dp *intel_dp)

{

	struct intel_digital_port *intel_dig_port = dp_to_dig_port(intel_dp);

	struct intel_encoder *encoder = &intel_dig_port->base;

	struct drm_i915_private *dev_priv = to_i915(encoder->base.dev);

	int max_dotclk = dev_priv->max_dotclk_freq;

	int ds_max_dotclk;



	int type = intel_dp->downstream_ports[0] & DP_DS_PORT_TYPE_MASK;



	if (type != DP_DS_PORT_TYPE_VGA)

		return max_dotclk;



	ds_max_dotclk = drm_dp_downstream_max_clock(intel_dp->dpcd,

						    intel_dp->downstream_ports);



	if (ds_max_dotclk != 0)

		max_dotclk = min(max_dotclk, ds_max_dotclk);



	return max_dotclk;

}



static enum drm_mode_status

intel_dp_mode_valid(struct drm_connector *connector,

		    struct drm_display_mode *mode)
@@ -199,7 +222,9 @@ intel_dp_mode_valid(struct drm_connector *connector, 
	struct drm_display_mode *fixed_mode = intel_connector->panel.fixed_mode;

	int target_clock = mode->clock;

	int max_rate, mode_rate, max_lanes, max_link_clock;

	int max_dotclk = to_i915(connector->dev)->max_dotclk_freq;

	int max_dotclk;



	max_dotclk = intel_dp_downstream_max_dotclock(intel_dp);



	if (is_edp(intel_dp) && fixed_mode) {

		if (mode->hdisplay > fixed_mode->hdisplay)