Re: [Intel-gfx] [PATCH 1/3] drm/debug: Expose connector's max supported bpc via debugfs

[Harry Wentland <harry.wentland@amd.com>]

On 2022-04-08 02:53, Bhanuprakash Modem wrote:
> It's useful to know the connector's max supported bpc for IGT
> testing. Expose it via a debugfs file on the connector "output_bpc".
> 
> Example: cat /sys/kernel/debug/dri/0/DP-1/output_bpc
> 
> Cc: Jani Nikula <jani.nikula@linux.intel.com>
> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
> Cc: Harry Wentland <harry.wentland@amd.com>
> Signed-off-by: Bhanuprakash Modem <bhanuprakash.modem@intel.com>
> ---
>  drivers/gpu/drm/drm_debugfs.c | 21 +++++++++++++++++++++
>  1 file changed, 21 insertions(+)
> 
> diff --git a/drivers/gpu/drm/drm_debugfs.c b/drivers/gpu/drm/drm_debugfs.c
> index 7f1b82dbaebb..33e5345c6f3e 100644
> --- a/drivers/gpu/drm/drm_debugfs.c
> +++ b/drivers/gpu/drm/drm_debugfs.c
> @@ -395,6 +395,23 @@ static int vrr_range_show(struct seq_file *m, void *data)
>  }
>  DEFINE_SHOW_ATTRIBUTE(vrr_range);
>  
> +/*
> + * Returns Connector's max supported bpc through debugfs file.
> + * Example usage: cat /sys/kernel/debug/dri/0/DP-1/max_bpc

/s/max_bpc/output_bpc

Btw, in amdgpu we have both max_bpc and output_bpc.

Harry

> + */
> +static int output_bpc_show(struct seq_file *m, void *data)
> +{
> +	struct drm_connector *connector = m->private;
> +
> +	if (connector->status != connector_status_connected)
> +		return -ENODEV;
> +
> +	seq_printf(m, "Maximum: %u\n", connector->display_info.bpc);
> +
> +	return 0;
> +}
> +DEFINE_SHOW_ATTRIBUTE(output_bpc);
> +
>  static const struct file_operations drm_edid_fops = {
>  	.owner = THIS_MODULE,
>  	.open = edid_open,
> @@ -437,6 +454,10 @@ void drm_debugfs_connector_add(struct drm_connector *connector)
>  	debugfs_create_file("vrr_range", S_IRUGO, root, connector,
>  			    &vrr_range_fops);
>  
> +	/* max bpc */
> +	debugfs_create_file("output_bpc", 0444, root, connector,
> +			    &output_bpc_fops);
> +
>  	if (connector->funcs->debugfs_init)
>  		connector->funcs->debugfs_init(connector, root);
>  }