[REGRESSION] [BISECTED] drm/sun4i: hdmi: No HDMI output with BananaPI M1 on 6.9

[Michael Klein]

On Mon, May 12, 2025 at 10:27:07PM +0200, Michael wrote:
>with v6.9 and later there is no output on the BananaPI HDMI connector.
>
>I have bisected the issue to the following commit:
>
>  358e76fd613a ("drm/sun4i: hdmi: Consolidate atomic_check and mode_valid")
>
>With this patch, sun4i_hdmi_connector_clock_valid() is occasionally 
>called with clock=0, causing the function to return MODE_NOCLOCK.
>In the old sun4i_hdmi_mode_valid() before the patch, mode->clock is 
>always!=0, maybe that gives someone a hint.

#regzbot introduced: 358e76fd613a