Re: [PATCH v3 4/6] drm/tidss: Set bus_format correctly from bridge/connector

[Laurent Pinchart <laurent.pinchart@ideasonboard.com>]

Hi Nikhil,

Thank you for the patch.

On Thu, Nov 19, 2020 at 09:31:32PM +0530, Nikhil Devshatwar wrote:
> Remove the old code to iterate over the bridge chain, as this is
> already done by the framework.
> The bridge state should have the negotiated bus format and flags.
> Use these from the bridge's state.
> If the bridge does not support format negotiation, error out
> and fail.
> 
> Signed-off-by: Nikhil Devshatwar <nikhil.nd@ti.com>
> Reviewed-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
> ---
> 
> Notes:
>     changes from v2:
>     * Remove the old code and use the flags from the bridge state
> 
>  drivers/gpu/drm/tidss/tidss_encoder.c | 36 +++++++++++----------------
>  1 file changed, 14 insertions(+), 22 deletions(-)
> 
> diff --git a/drivers/gpu/drm/tidss/tidss_encoder.c b/drivers/gpu/drm/tidss/tidss_encoder.c
> index e278a9c89476..08d5083c5508 100644
> --- a/drivers/gpu/drm/tidss/tidss_encoder.c
> +++ b/drivers/gpu/drm/tidss/tidss_encoder.c
> @@ -21,37 +21,29 @@ static int tidss_encoder_atomic_check(struct drm_encoder *encoder,
>  {
>  	struct drm_device *ddev = encoder->dev;
>  	struct tidss_crtc_state *tcrtc_state = to_tidss_crtc_state(crtc_state);
> -	struct drm_display_info *di = &conn_state->connector->display_info;
> +	struct drm_bridge_state *bstate;
>  	struct drm_bridge *bridge;
> -	bool bus_flags_set = false;
>  
>  	dev_dbg(ddev->dev, "%s\n", __func__);
>  
> -	/*
> -	 * Take the bus_flags from the first bridge that defines
> -	 * bridge timings, or from the connector's display_info if no
> -	 * bridge defines the timings.
> -	 */
> -	drm_for_each_bridge_in_chain(encoder, bridge) {
> -		if (!bridge->timings)
> -			continue;
> -
> -		tcrtc_state->bus_flags = bridge->timings->input_bus_flags;
> -		bus_flags_set = true;
> -		break;
> +	/* Copy the bus_format and flags from the first bridge's state */
> +	bridge = drm_bridge_chain_get_first_bridge(encoder);
> +	bstate = drm_atomic_get_new_bridge_state(crtc_state->state, bridge);
> +	if (bstate) {
> +		tcrtc_state->bus_format = bstate->input_bus_cfg.format;
> +		tcrtc_state->bus_flags = bstate->input_bus_cfg.flags;
> +	} else {
> +		dev_err(ddev->dev, "Could not get the bridge state\n");
> +		return -EINVAL;
>  	}

I'd write this

	bstate = drm_atomic_get_new_bridge_state(crtc_state->state, bridge);
	if (!bstate) {
		dev_err(ddev->dev, "Could not get the bridge state\n");
		return -EINVAL;
	}

	tcrtc_state->bus_format = bstate->input_bus_cfg.format;
	tcrtc_state->bus_flags = bstate->input_bus_cfg.flags;
>  
> -	if (!di->bus_formats || di->num_bus_formats == 0)  {
> -		dev_err(ddev->dev, "%s: No bus_formats in connected display\n",
> -			__func__);
> +	if (tcrtc_state->bus_format == 0 ||
> +	    tcrtc_state->bus_format == MEDIA_BUS_FMT_FIXED) {
> +
> +		dev_err(ddev->dev, "Bridge connected to the encoder did not specify media bus format\n");
>  		return -EINVAL;
>  	}
>  
> -	// XXX any cleaner way to set bus format and flags?
> -	tcrtc_state->bus_format = di->bus_formats[0];
> -	if (!bus_flags_set)
> -		tcrtc_state->bus_flags = di->bus_flags;
> -
>  	return 0;
>  }
>  

-- 
Regards,

Laurent Pinchart
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