[PATCH v2] drm/i915/backlight: Fix divide by 0 error in i9xx_set_backlight

[Jani Nikula]

On Tue, 19 Aug 2025, Suraj Kandpal <suraj.kandpal at intel.com> wrote:
> pwm_level_max maybe 0 we do throw a warning but move ahead with
> execution which may later cause a /0 error.
>
> --v2
> -return if the warn_on gets hit [Jani]
>
> Signed-off-by: Suraj Kandpal <suraj.kandpal at intel.com>

Reviewed-by: Jani Nikula <jani.nikula at intel.com>


> ---
>  drivers/gpu/drm/i915/display/intel_backlight.c | 3 ++-
>  1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/i915/display/intel_backlight.c b/drivers/gpu/drm/i915/display/intel_backlight.c
> index e007380e9a63..3b14f929825a 100644
> --- a/drivers/gpu/drm/i915/display/intel_backlight.c
> +++ b/drivers/gpu/drm/i915/display/intel_backlight.c
> @@ -236,7 +236,8 @@ static void i9xx_set_backlight(const struct drm_connector_state *conn_state, u32
>  	struct intel_panel *panel = &connector->panel;
>  	u32 tmp, mask;
>  
> -	drm_WARN_ON(display->drm, panel->backlight.pwm_level_max == 0);
> +	if (drm_WARN_ON(display->drm, panel->backlight.pwm_level_max == 0))
> +		return;
>  
>  	if (panel->backlight.combination_mode) {
>  		struct pci_dev *pdev = to_pci_dev(display->drm->dev);

-- 
Jani Nikula, Intel