[PATCH v2] drm: rcar-du: dw-hdmi: Reject modes with a too high clock frequency

[Geert Uytterhoeven]

Hi Laurent,

On Tue, Dec 4, 2018 at 5:36 PM Laurent Pinchart
<laurent.pinchart+renesas at ideasonboard.com> wrote:
> Implement a .mode_valid() handler in the R-Car glue layer to reject
> modes with an unsupported clock frequency.
>
> Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas at ideasonboard.com>

Thanks for your patch!

> --- a/drivers/gpu/drm/rcar-du/rcar_dw_hdmi.c
> +++ b/drivers/gpu/drm/rcar-du/rcar_dw_hdmi.c
> @@ -35,6 +35,20 @@ static const struct rcar_hdmi_phy_params rcar_hdmi_phy_params[] = {
>         { ~0UL,      0x0000, 0x0000, 0x0000 },
>  };
>
> +static enum drm_mode_status
> +rcar_hdmi_mode_valid(struct drm_connector *connector,
> +                    const struct drm_display_mode *mode)
> +{
> +       /*
> +        * The maximum supported clock frequency is 297 MHz, as shown in the PHY
> +        * parameters table.
> +        */
> +       if (mode->clock > 297000)
> +               return MODE_CLOCK_HIGH;

Perhaps you need a check for the lower limit (25 MHz), too?

> +
> +       return MODE_OK;
> +}

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert at linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds