Re: [Intel-gfx] [PATCH v2] drm/i915/tv: avoid possible division by zero

[Su Hui]

On 2023/7/25 13:51, Dan Carpenter wrote:
> The reason why the first five attempts had bugs is because we are
> trying to write it in the most complicated way possible, shifting by
> logical not what?
Wonderful! Should I add your name as signed-of-by?
I will send a v3 patch later.
Really thanks for your help!

Su Hui

> regards,
> dan carpenter
>
> diff --git a/drivers/gpu/drm/i915/display/intel_tv.c b/drivers/gpu/drm/i915/display/intel_tv.c
> index 36b479b46b60..6997b6cb1df2 100644
> --- a/drivers/gpu/drm/i915/display/intel_tv.c
> +++ b/drivers/gpu/drm/i915/display/intel_tv.c
> @@ -988,7 +988,13 @@ intel_tv_mode_to_mode(struct drm_display_mode *mode,
>   		      const struct tv_mode *tv_mode,
>   		      int clock)
>   {
> -	mode->clock = clock / (tv_mode->oversample >> !tv_mode->progressive);
> +	int div = tv_mode->oversample;
> +
> +	if (!tv_mode->progressive)
> +		div >>= 1;
> +	if (div == 0)
> +		div = 1;
> +	mode->clock = clock / div;
>   
>   	/*
>   	 * tv_mode horizontal timings:
> @@ -1135,6 +1141,8 @@ intel_tv_get_config(struct intel_encoder *encoder,
>   		break;
>   	default:
>   		tv_mode.oversample = 1;
> +		WARN_ON_ONCE(!tv_mode.progressive);
> +		tv_mode.progressive = true;
>   		break;
>   	}
>