From mboxrd@z Thu Jan  1 00:00:00 1970
From: Keith Packard <keithp@keithp.com>
Subject: Re: [PATCH 7/8] drm/i915: Re-enable self-refresh
Date: Fri, 18 Mar 2011 08:22:16 -0700
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On Fri, 18 Mar 2011 08:02:09 +0000, Chris Wilson <chris@chris-wilson.co.uk>=
 wrote:

> A broken implementation of is_pot() prevented the detection of when a
> singular pipe was enabled.

> -	return mask && (mask & -mask) =3D=3D 0;
> +	return mask && (mask & -mask) =3D=3D mask;

I think the form

        mask && (mask & (mask - 1)) =3D=3D 0

is easier to reason about.

But, your fix is also correct as it finds the lowest bit set in 'mask'
and checks to see if that is the same as mask.

Reviewed-by: Keith Packard <keithp@keithp.com>

=2D-=20
keith.packard@intel.com

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