From mboxrd@z Thu Jan  1 00:00:00 1970
From: Ville =?iso-8859-1?Q?Syrj=E4l=E4?= <ville.syrjala@linux.intel.com>
Subject: Re: [PATCH] drm/i915: Fix erroneous conversion to u8
Date: Fri, 8 Aug 2014 21:32:20 +0300
Message-ID: <20140808183220.GI4193@intel.com>
References: <20140808175623.GH4193@intel.com>
 <1407522357-18474-1-git-send-email-damien.lespiau@intel.com>
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To: Damien Lespiau <damien.lespiau@intel.com>
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On Fri, Aug 08, 2014 at 07:25:57PM +0100, Damien Lespiau wrote:
> adj was defined as u8. The issue is last_adj can be negative and adj is
> initialized with:
> =

>   adj =3D dev_priv->rps.last_adj;
> =

> and we were also happily doing things like:
> =

>   if (adj < 0)
> =

> (thank static analysers!)
> =

> v2: Make new_delay an int in case we overflow the u8 in the intermediate
>     computations. new_delay will get clamped at the end anyway. (Ville)
> =

> Cc: Deepak S <deepak.s@linux.intel.com>
> Cc: Ville Syrj=E4l=E4 <ville.syrjala@linux.intel.com>
> Signed-off-by: Damien Lespiau <damien.lespiau@intel.com>

Reviewed-by: Ville Syrj=E4l=E4 <ville.syrjala@linux.intel.com>

> ---
>  drivers/gpu/drm/i915/i915_irq.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> =

> diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_=
irq.c
> index 9fdf738..8e6729e 100644
> --- a/drivers/gpu/drm/i915/i915_irq.c
> +++ b/drivers/gpu/drm/i915/i915_irq.c
> @@ -1327,10 +1327,10 @@ static u32 vlv_c0_residency(struct drm_i915_priva=
te *dev_priv,
>   * @dev_priv: DRM device private
>   *
>   */
> -static u32 vlv_calc_delay_from_C0_counters(struct drm_i915_private *dev_=
priv)
> +static int vlv_calc_delay_from_C0_counters(struct drm_i915_private *dev_=
priv)
>  {
>  	u32 residency_C0_up =3D 0, residency_C0_down =3D 0;
> -	u8 new_delay, adj;
> +	int new_delay, adj;
>  =

>  	dev_priv->rps.ei_interrupt_count++;
>  =

> -- =

> 1.8.3.1

-- =

Ville Syrj=E4l=E4
Intel OTC