[2/3] drm/sun4i: rgb: Fix potential division by zero

[Giulio Benetti]

Il 21/02/2018 13:57, Maxime Ripard ha scritto:
> In the case where mode_valid callback of our RGB connector was called
> before mode_set was being called, the range of dividers would not be set,
> resulting in a division by zero later on in the clk_round_rate logic.
> 
> Set the range of dividers before calling clk_round_rate to fix this.
> 
> Signed-off-by: Maxime Ripard <maxime.ripard at bootlin.com>
Tested-by: Giulio Benetti <giulio.benetti at micronovasrl.com>

Before crtc couldn't be added because of min=0 and max=0.
Now they're initiliazed and crtc is added correctly.
> ---
>   drivers/gpu/drm/sun4i/sun4i_rgb.c | 2 ++
>   1 file changed, 2 insertions(+)
> 
> diff --git a/drivers/gpu/drm/sun4i/sun4i_rgb.c b/drivers/gpu/drm/sun4i/sun4i_rgb.c
> index 832f8f9bc47f..b8da5a50a61d 100644
> --- a/drivers/gpu/drm/sun4i/sun4i_rgb.c
> +++ b/drivers/gpu/drm/sun4i/sun4i_rgb.c
> @@ -92,6 +92,8 @@ static int sun4i_rgb_mode_valid(struct drm_connector *connector,
>   
>   	DRM_DEBUG_DRIVER("Vertical parameters OK\n");
>   
> +	tcon->dclk_min_div = 6;
> +	tcon->dclk_max_div = 127;
>   	rounded_rate = clk_round_rate(tcon->dclk, rate);
>   	if (rounded_rate < rate)
>   		return MODE_CLOCK_LOW;
> 


-- 
Giulio Benetti
CTO

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