-----Original Message-----
From: Intel-xe <[email protected]> On Behalf Of Suraj
Kandpal
Sent: Monday, June 9, 2025 9:46 AM
To: [email protected]; [email protected]
Cc: Nautiyal, Ankit K <[email protected]>; Kandpal, Suraj
<[email protected]>
Subject: [PATCH] drm/i915/xe3lpd: Prune modes for YUV420
>
> We only support resolution up to 4k for single pipe when using
> YUV420 format so we prune these modes and restrict the plane size
> at src. This is because pipe scaling will not support YUV420 scaling
> for hwidth > 4096.
>
> --v2
> -Use output format to check [Ville]
> -Add Bspec references
> -Modify commit messge to point to why this is needed
>
> Bspec: 49247, 50441
> Signed-off-by: Suraj Kandpal <[email protected]>
> ---
> drivers/gpu/drm/i915/display/intel_dp.c | 12 +++++++++---
> 1 file changed, 9 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_dp.c
> b/drivers/gpu/drm/i915/display/intel_dp.c
> index d04609460e8c..2691eeb50a26 100644
> --- a/drivers/gpu/drm/i915/display/intel_dp.c
> +++ b/drivers/gpu/drm/i915/display/intel_dp.c
> @@ -1419,6 +1419,7 @@ intel_dp_mode_valid(struct drm_connector *_connector,
> struct intel_display *display = to_intel_display(_connector->dev);
> struct intel_connector *connector = to_intel_connector(_connector);
> struct intel_dp *intel_dp = intel_attached_dp(connector);
> + enum intel_output_format sink_format, output_format;
> const struct drm_display_mode *fixed_mode;
> int target_clock = mode->clock;
> int max_rate, mode_rate, max_lanes, max_link_clock;
> @@ -1452,6 +1453,14 @@ intel_dp_mode_valid(struct drm_connector *_connector,
> mode->hdisplay,
> target_clock);
> max_dotclk *= num_joined_pipes;
>
> + sink_format = intel_dp_sink_format(connector, mode);
> + output_format = intel_dp_output_format(connector, sink_format);
> + if (num_joined_pipes == 1) {
> + if (output_format == INTEL_OUTPUT_FORMAT_YCBCR420 &&
> + mode->hdisplay > 4096)
> + return MODE_NO_420;
> + }
These nested if statements can probably be combined:
"""
if (num_joined_pipes == 1 &&
output_format == INTEL_OUTPUT_FORMAT_YCBCR420 &&
mode->hdisplay > 4096)
return MODE_NO_420;
"""
However, I think this is a matter of style preference, so I won't block on it.
And if there's a practical reason the if statements are broken up like this,
then
that's also good enough reason to leave it as is.
Otherwise:
Reviewed-by: Jonathan Cavitt <[email protected]>
-Jonathan Cavitt
> +
> if (target_clock > max_dotclk)
> return MODE_CLOCK_HIGH;
>
> @@ -1467,11 +1476,8 @@ intel_dp_mode_valid(struct drm_connector *_connector,
>
> intel_dp_mode_min_output_bpp(connector, mode));
>
> if (intel_dp_has_dsc(connector)) {
> - enum intel_output_format sink_format, output_format;
> int pipe_bpp;
>
> - sink_format = intel_dp_sink_format(connector, mode);
> - output_format = intel_dp_output_format(connector, sink_format);
> /*
> * TBD pass the connector BPC,
> * for now U8_MAX so that max BPC on that platform would be
> picked
> --
> 2.34.1
>
>
