On Tue, 29 Mar 2022, Bhanuprakash Modem <bhanuprakash.modem@xxxxxxxxx> wrote:
> This new debugfs will expose the connector's max supported bpc
> and the bpc currently using. It is very useful for verifying
> whether we enter the correct output color depth from IGT.
>
> Example:
> cat /sys/kernel/debug/dri/0/DP-1/output_bpc
> Current: 8
> Maximum: 10
>
> V2: Add connector's max bpc to i915_display_info
>
> Cc: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
> Cc: Uma Shankar <uma.shankar@xxxxxxxxx>
> Cc: Swati Sharma <swati2.sharma@xxxxxxxxx>
> Signed-off-by: Bhanuprakash Modem <bhanuprakash.modem@xxxxxxxxx>
> ---
> .../drm/i915/display/intel_display_debugfs.c | 46 +++++++++++++++++++
> 1 file changed, 46 insertions(+)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_display_debugfs.c b/drivers/gpu/drm/i915/display/intel_display_debugfs.c
> index c1e74a13a0828..694d27f3b109c 100644
> --- a/drivers/gpu/drm/i915/display/intel_display_debugfs.c
> +++ b/drivers/gpu/drm/i915/display/intel_display_debugfs.c
> @@ -663,6 +663,8 @@ static void intel_connector_info(struct seq_file *m,
> seq_puts(m, "\tHDCP version: ");
> intel_hdcp_info(m, intel_connector);
>
> + seq_printf(m, "\tmax bpc: %u\n", connector->display_info.bpc);
> +
> intel_panel_info(m, intel_connector);
>
> seq_printf(m, "\tmodes:\n");
> @@ -2275,6 +2277,47 @@ static const struct file_operations i915_dsc_bpp_fops = {
> .write = i915_dsc_bpp_write
> };
>
> +/*
> + * Returns the maximum output bpc for the connector.
> + * Example usage: cat /sys/kernel/debug/dri/0/DP-1/output_bpc
> + */
> +static int output_bpc_show(struct seq_file *m, void *data)
> +{
> + struct drm_connector *connector = m->private;
> + struct drm_device *dev = connector->dev;
> + struct drm_crtc *crtc;
> + struct intel_crtc_state *crtc_state;
> + struct intel_encoder *encoder = intel_attached_encoder(to_intel_connector(connector));
> + int res;
> +
> + if (!encoder)
> + return -ENODEV;
> +
> + res = drm_modeset_lock_single_interruptible(&dev->mode_config.connection_mutex);
> + if (res)
> + return res;
> +
> + crtc = connector->state->crtc;
> + if (connector->status != connector_status_connected || !crtc) {
> + res = -ENODEV;
> + goto unlock;
> + }
> +
> + crtc_state = to_intel_crtc_state(crtc->state);
> + if (!crtc_state->hw.active)
> + goto unlock;
> +
> + seq_printf(m, "Current: %u\n", crtc_state->pipe_bpp / 3);
> + seq_printf(m, "Maximum: %u\n", connector->display_info.bpc);
> + res = 0;
> +
> +unlock:
> + drm_modeset_unlock(&dev->mode_config.connection_mutex);
> +
> + return res;
> +}
> +DEFINE_SHOW_ATTRIBUTE(output_bpc);
Looks like an excessive amount of code for a single value.
BR,
Jani.
> +
> /**
> * intel_connector_debugfs_add - add i915 specific connector debugfs files
> * @connector: pointer to a registered drm_connector
> @@ -2330,6 +2373,9 @@ void intel_connector_debugfs_add(struct intel_connector *intel_connector)
> connector->connector_type == DRM_MODE_CONNECTOR_HDMIB)
> debugfs_create_file("i915_lpsp_capability", 0444, root,
> connector, &i915_lpsp_capability_fops);
> +
> + debugfs_create_file("output_bpc", 0444, root,
> + connector, &output_bpc_fops);
> }
>
> /**
--
Jani Nikula, Intel Open Source Graphics Center
