On Wed, Jul 06, 2016 at 02:04:52PM +0300, Mika Kahola wrote:
> 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)
>
> Signed-off-by: Mika Kahola <mika.kahola@xxxxxxxxx>
> ---
> drivers/gpu/drm/i915/intel_dp.c | 26 ++++++++++++++++++++++++++
> 1 file changed, 26 insertions(+)
>
> diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
> index ffa43ec..76a654e 100644
> --- a/drivers/gpu/drm/i915/intel_dp.c
> +++ b/drivers/gpu/drm/i915/intel_dp.c
> @@ -190,6 +190,20 @@ 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_clock(struct intel_dp *intel_dp, int clock)
> +{
> + int dp_ds_clk;
> +
> + dp_ds_clk = drm_dp_downstream_max_clock(intel_dp->dpcd,
> + intel_dp->downstream_ports);
> +
> + if (dp_ds_clk == 0)
> + return clock;
> +
> + return min(clock, dp_ds_clk);
> +}
> +
> static enum drm_mode_status
> intel_dp_mode_valid(struct drm_connector *connector,
> struct drm_display_mode *mode)
> @@ -201,6 +215,18 @@ intel_dp_mode_valid(struct drm_connector *connector,
> int max_rate, mode_rate, max_lanes, max_link_clock;
> int max_dotclk = to_i915(connector->dev)->max_dotclk_freq;
>
> + bool is_branch_device = intel_dp->dpcd[DP_DOWNSTREAMPORT_PRESENT] &
> + DP_DWN_STRM_PORT_PRESENT;
> + int type;
> +
> + if (is_branch_device) {
Shouldn't we move this check into the drm dp helper? It can always return
0 for "no downstream port restrictions".
> + type = intel_dp->downstream_ports[0] & DP_DS_PORT_TYPE_MASK;
> +
> + if (type == DP_DS_PORT_TYPE_VGA)
Same here.
-Daniel
> + max_dotclk = intel_dp_downstream_max_clock(intel_dp,
> + max_dotclk);
> + }
> +
> if (is_edp(intel_dp) && fixed_mode) {
> if (mode->hdisplay > fixed_mode->hdisplay)
> return MODE_PANEL;
> --
> 1.9.1
>
--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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