[PATCH 2/5] drm/tidss: Set bus_format correctly from bridge/connector

[Laurent Pinchart]

Hi Nikhil,

Thank you for the patch.

On Fri, Oct 16, 2020 at 04:09:14PM +0530, Nikhil Devshatwar wrote:
> When there is a chain of bridges attached to the encoder,
> the bus_format should be ideally set from the input format of the
> first bridge in the chain.
> 
> Use the bridge state to get the negotiated bus_format.
> If the bridge does not support format negotiation, error out
> and fail.
> 
> Signed-off-by: Nikhil Devshatwar <nikhil.nd at ti.com>
> ---
>  drivers/gpu/drm/tidss/tidss_encoder.c | 16 +++++++++++-----
>  1 file changed, 11 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/gpu/drm/tidss/tidss_encoder.c b/drivers/gpu/drm/tidss/tidss_encoder.c
> index e278a9c89476..ae7f134754b7 100644
> --- a/drivers/gpu/drm/tidss/tidss_encoder.c
> +++ b/drivers/gpu/drm/tidss/tidss_encoder.c
> @@ -22,6 +22,7 @@ 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;
>  
> @@ -41,14 +42,19 @@ static int tidss_encoder_atomic_check(struct drm_encoder *encoder,
>  		break;
>  	}
>  
> -	if (!di->bus_formats || di->num_bus_formats == 0)  {
> -		dev_err(ddev->dev, "%s: No bus_formats in connected display\n",
> -			__func__);
> +	/* Copy the bus_format from the input_bus_format of first bridge */
> +	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;
> +
> +	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;

Shouldn't the flags also be retrieved from the bridge state ?

>  

-- 
Regards,

Laurent Pinchart