[PATCH] drm/mediatek: mtk-dpi: Set out_fmt from config if not the last bridge

[Chun-Kuang Hu]

Hi, Hsin-yi:

Hsin-Yi Wang <hsinyi at chromium.org> 於 2021年7月12日 週一 下午5:47寫道：
>
> atomic_get_output_bus_fmts() is only called when the bridge is the last
> element in the bridge chain.
>
> If mtk-dpi is not the last bridge, the format of output_bus_cfg is
> MEDIA_BUS_FMT_FIXED, and mtk_dpi_dual_edge() will fail to write correct
> value to regs.

Applied to mediatek-drm-fixes [1], thanks.

[1] https://git.kernel.org/pub/scm/linux/kernel/git/chunkuang.hu/linux.git/log/?h=mediatek-drm-fixes

Regards,
Chun-Kuang.

>
> Fixes: ec8747c52434 ("drm/mediatek: dpi: Add bus format negotiation")
> Signed-off-by: Hsin-Yi Wang <hsinyi at chromium.org>
> ---
>  drivers/gpu/drm/mediatek/mtk_dpi.c | 4 ++++
>  1 file changed, 4 insertions(+)
>
> diff --git a/drivers/gpu/drm/mediatek/mtk_dpi.c b/drivers/gpu/drm/mediatek/mtk_dpi.c
> index bced555648b01..25c565f9179cc 100644
> --- a/drivers/gpu/drm/mediatek/mtk_dpi.c
> +++ b/drivers/gpu/drm/mediatek/mtk_dpi.c
> @@ -610,6 +610,10 @@ static int mtk_dpi_bridge_atomic_check(struct drm_bridge *bridge,
>
>         out_bus_format = bridge_state->output_bus_cfg.format;
>
> +       if (out_bus_format == MEDIA_BUS_FMT_FIXED)
> +               if (dpi->conf->num_output_fmts)
> +                       out_bus_format = dpi->conf->output_fmts[0];
> +
>         dev_dbg(dpi->dev, "input format 0x%04x, output format 0x%04x\n",
>                 bridge_state->input_bus_cfg.format,
>                 bridge_state->output_bus_cfg.format);
> --
> 2.32.0.93.g670b81a890-goog
>