[Intel-gfx] [PATCH] drm/i915: Fix divide by zero on watermark update

[Paulo Zanoni]

2015-07-16 13:00 GMT-03:00 Mika Kuoppala <mika.kuoppala at linux.intel.com>:
> Fix divide by zero if we end up updating the watermarks
> with zero dotclock.
>
> This is a stop gap measure to allow module load in cases
> where our state keeping fails.

Shouldn't we WARN() here?

>
> Cc: Damien Lespiau <damien.lespiau at intel.com>
> Signed-off-by: Mika Kuoppala <mika.kuoppala at intel.com>
> ---
>  drivers/gpu/drm/i915/intel_pm.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
> index 5eeddc9..755f0e8 100644
> --- a/drivers/gpu/drm/i915/intel_pm.c
> +++ b/drivers/gpu/drm/i915/intel_pm.c
> @@ -3316,8 +3316,10 @@ skl_compute_linetime_wm(struct drm_crtc *crtc, struct skl_pipe_wm_parameters *p)
>         if (!to_intel_crtc(crtc)->active)
>                 return 0;
>
> -       return DIV_ROUND_UP(8 * p->pipe_htotal * 1000, p->pixel_rate);
> +       if (p->pixel_rate == 0)
> +               return 0;
>
> +       return DIV_ROUND_UP(8 * p->pipe_htotal * 1000, p->pixel_rate);
>  }
>
>  static void skl_compute_transition_wm(struct drm_crtc *crtc,
> --
> 2.1.4
>
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-- 
Paulo Zanoni