Re: [PATCH] drm/i915: fix intel_framebuffer_pitch_for_width for <8bpp

From: "Ville Syrjälä" <ville.syrjala@linux.intel.com>
To: Jesse Barnes <jbarnes@virtuousgeek.org>
Cc: intel-gfx@lists.freedesktop.org
Subject: Re: [PATCH] drm/i915: fix intel_framebuffer_pitch_for_width for <8bpp
Date: Tue, 2 Apr 2013 21:08:10 +0300	[thread overview]
Message-ID: <20130402180810.GV4469@intel.com> (raw)
In-Reply-To: <1364923691-3692-1-git-send-email-jbarnes@virtuousgeek.org>

On Tue, Apr 02, 2013 at 10:28:11AM -0700, Jesse Barnes wrote:
> As Imre pointed out, this will do the wrong thing.
> 
> Reported-by: Imre Deak <imre.deak@intel.com>
> Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>

We don't actually support anything w/ bpp%8!=0, so either works.
Actually, for something like bpp=4, the original code might even be
more correct. But I don't really want to think about <8bpp stuff,
so I won't object to the patch.

> ---
>  drivers/gpu/drm/i915/intel_drv.h |    2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
> index 37f4bb3..18f0547 100644
> --- a/drivers/gpu/drm/i915/intel_drv.h
> +++ b/drivers/gpu/drm/i915/intel_drv.h
> @@ -137,7 +137,7 @@ struct intel_framebuffer {
>  inline static u32
>  intel_framebuffer_pitch_for_width(int width, int bpp)
>  {
> -	u32 pitch = DIV_ROUND_UP(width * bpp, 8);
> +	u32 pitch = width * DIV_ROUND_UP(bpp, 8);
>  	return ALIGN(pitch, 64);
>  }
>  
> -- 
> 1.7.9.5
> 
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-- 
Ville Syrjälä
Intel OTC