Hi Neil
Sorry, just some trivial spelling fixes.
On Mon, 2022-01-17 at 15:17 +0100, Neil Armstrong wrote:
> When the dw-hdmi bridge is in first place of the bridge chain, this
> means there is now way
no way
> to select an input format of the dw-hdmi HW
> component.
>
> Since introduction of display-connector, negociation
:%s/negociation/negotiation/g
> was broken since
> the dw-hdmi negociation code only worked when the dw-hdmi bridge was
> in last position of the bridge chain or behind another bridge also
> supporting input & output format negociation.
>
> Commit 0656d1285b79 ("drm/bridge: display-connector: implement bus fmts callbacks")
> was introduced to make negociation work again by making display-connector
> act as a pass-through concerning input & output format negociation.
>
> But in the case were
where
> the dw-hdmi was single in the bridge chain, for
> example on Renesas SoCs, with the disply-connector
display-connector
> bridge the dw-hdmi
> is no more single, breaking output format.
>
> Reported-by: Biju Das <biju.das.jz@xxxxxxxxxxxxxx>
> Bisected-by: Kieran Bingham <kieran.bingham+renesas@xxxxxxxxxxxxxxxx>
> Tested-by: Kieran Bingham <kieran.bingham+renesas@xxxxxxxxxxxxxxxx>
> Fixes: 0656d1285b79 ("drm/bridge: display-connector: implement bus fmts callbacks").
> Signed-off-by: Neil Armstrong <narmstrong@xxxxxxxxxxxx>
> ---
> drivers/gpu/drm/bridge/synopsys/dw-hdmi.c | 9 +++++++--
> 1 file changed, 7 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
> index 54d8fdad395f..9f2e1cac0ae2 100644
> --- a/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
> +++ b/drivers/gpu/drm/bridge/synopsys/dw-hdmi.c
> @@ -2551,8 +2551,9 @@ static u32 *dw_hdmi_bridge_atomic_get_output_bus_fmts(struct drm_bridge *bridge,
> if (!output_fmts)
> return NULL;
>
> - /* If dw-hdmi is the only bridge, avoid negociating with ourselves */
> - if (list_is_singular(&bridge->encoder->bridge_chain)) {
> + /* If dw-hdmi is the first or only bridge, avoid negociating with ourselves */
> + if (list_is_singular(&bridge->encoder->bridge_chain) ||
> + list_is_first(&bridge->chain_node, &bridge->encoder->bridge_chain)) {
> *num_output_fmts = 1;
> output_fmts[0] = MEDIA_BUS_FMT_FIXED;
>
> @@ -2673,6 +2674,10 @@ static u32 *dw_hdmi_bridge_atomic_get_input_bus_fmts(struct drm_bridge *bridge,
> if (!input_fmts)
> return NULL;
>
> + /* If dw-hdmi is the first bridge fall-back to safe output format */
> + if (list_is_first(&bridge->chain_node, &bridge->encoder->bridge_chain))
> + output_fmt = MEDIA_BUS_FMT_FIXED;
> +
> switch (output_fmt) {
> /* If MEDIA_BUS_FMT_FIXED is tested, return default bus format */
> case MEDIA_BUS_FMT_FIXED:
Cheers
Marcel
