[Intel-gfx] [PATCH 38/49] drm/i915: check for div-by-zero in vlv_PLL_is_optimal

[Jesse Barnes]

On 03/17/2015 02:40 AM, Imre Deak wrote:
> Signed-off-by: Imre Deak <imre.deak at intel.com>
> ---
>  drivers/gpu/drm/i915/intel_display.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> index 7feb047..5874512 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -786,6 +786,9 @@ static bool vlv_PLL_is_optimal(struct drm_device *dev, int target_freq,
>  			       unsigned int best_error_ppm,
>  			       unsigned int *error_ppm)
>  {
> +	if (WARN_ON_ONCE(!target_freq))
> +		return false;
> +
>  	*error_ppm = div_u64(1000000ULL *
>  				abs(target_freq - calculated_clock->dot),
>  			     target_freq);
> 

Thank you.  This one bites a lot in debug.

Reviewed-by: Jesse Barnes <jbarnes at virtuousgeek.org>