Am Montag, dem 04.10.2021 um 09:27 +0200 schrieb Guido Günther:
> Components further up in the chain might ask us for supported formats.
>
> Without this MEDIA_BUS_FMT_FIXED is assumed which then breaks display
> output with mxsfb since it can't determine a proper bus format.
>
> We handle the bus formats that correspond to the DSI formats the bridge
> can potentially output (see chapter 13.6 of the i.MX 8MQ reference
> manual) - which matches what xsfb can input.
>
> Fixes: b776b0f00f24 ("drm: mxsfb: Use bus_format from the nearest bridge if present")
>
> Signed-off-by: Guido Günther <agx@xxxxxxxxxxx>
Reviewed-by: Lucas Stach <l.stach@xxxxxxxxxxxxxx>
> ---
> drivers/gpu/drm/bridge/nwl-dsi.c | 35 ++++++++++++++++++++++++++++++++
> 1 file changed, 35 insertions(+)
>
> diff --git a/drivers/gpu/drm/bridge/nwl-dsi.c b/drivers/gpu/drm/bridge/nwl-dsi.c
> index a251cc1f088f..27c80d36846b 100644
> --- a/drivers/gpu/drm/bridge/nwl-dsi.c
> +++ b/drivers/gpu/drm/bridge/nwl-dsi.c
> @@ -1234,6 +1234,40 @@ static void nwl_dsi_bridge_detach(struct drm_bridge *bridge)
> drm_of_panel_bridge_remove(dsi->dev->of_node, 1, 0);
> }
>
> +static u32 *nwl_bridge_atomic_get_input_bus_fmts(struct drm_bridge *bridge,
> + struct drm_bridge_state *bridge_state,
> + struct drm_crtc_state *crtc_state,
> + struct drm_connector_state *conn_state,
> + u32 output_fmt,
> + unsigned int *num_input_fmts)
> +{
> + u32 *input_fmts, input_fmt;
> +
> + *num_input_fmts = 0;
> +
> + switch (output_fmt) {
> + /* If MEDIA_BUS_FMT_FIXED is tested, return default bus format */
> + case MEDIA_BUS_FMT_FIXED:
> + input_fmt = MEDIA_BUS_FMT_RGB888_1X24;
> + break;
> + case MEDIA_BUS_FMT_RGB888_1X24:
> + case MEDIA_BUS_FMT_RGB666_1X18:
> + case MEDIA_BUS_FMT_RGB565_1X16:
> + input_fmt = output_fmt;
> + break;
> + default:
> + return NULL;
> + }
> +
> + input_fmts = kcalloc(1, sizeof(*input_fmts), GFP_KERNEL);
> + if (!input_fmts)
> + return NULL;
> + input_fmts[0] = input_fmt;
> + *num_input_fmts = 1;
> +
> + return input_fmts;
> +}
> +
> static const struct drm_bridge_funcs nwl_dsi_bridge_funcs = {
> .atomic_duplicate_state = drm_atomic_helper_bridge_duplicate_state,
> .atomic_destroy_state = drm_atomic_helper_bridge_destroy_state,
> @@ -1241,6 +1275,7 @@ static const struct drm_bridge_funcs nwl_dsi_bridge_funcs = {
> .atomic_check = nwl_dsi_bridge_atomic_check,
> .atomic_enable = nwl_dsi_bridge_atomic_enable,
> .atomic_disable = nwl_dsi_bridge_atomic_disable,
> + .atomic_get_input_bus_fmts = nwl_bridge_atomic_get_input_bus_fmts,
> .mode_set = nwl_dsi_bridge_mode_set,
> .mode_valid = nwl_dsi_bridge_mode_valid,
> .attach = nwl_dsi_bridge_attach,
