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From:   James Hughes <james.hughes@raspberrypi.com>
Date:   Thu, 20 Feb 2020 09:44:03 +0000
Message-ID: <CAJ+9seGY3owufzm4WZwTQXQA9BonyamCCWCrazA3bukEkGixug@mail.gmail.com>
Subject: Re: [PATCH] GPU: DRM: VC4/V3D Replace wait_for macros in to remove
 use of msleep
To:     Eric Anholt <eric@anholt.net>
Cc:     David Airlie <airlied@linux.ie>,
        DRI Development <dri-devel@lists.freedesktop.org>,
        linux-kernel@vger.kernel.org
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On Wed, 19 Feb 2020 at 22:51, Eric Anholt <eric@anholt.net> wrote:
>
> On Mon, Feb 17, 2020 at 7:41 AM James Hughes
> <james.hughes@raspberrypi.com> wrote:
> >
> > The wait_for macro's for Broadcom VC4 and V3D drivers used msleep
> > which is inappropriate due to its inaccuracy at low values (minimum
> > wait time is about 30ms on the Raspberry Pi).
> >
> > This patch replaces the macro with the one from the Intel i915 version
> > which uses usleep_range to provide more accurate waits.
> >
> > Signed-off-by: James Hughes <james.hughes@raspberrypi.com>
>
> To apply this, we're going to want to split the patch up between v3d
> (with a fixes tag to the introduction of the driver, since it's a
> pretty critical fix) and vc4 (where it's used in KMS, and we're pretty
> sure we want it but changing timing like this in KMS paths is risky so
> we don't want to backport to stable).  And adjust the commit messages
> to have consistent prefixes to the rest of the commits to those
> drivers.
>
> I've been fighting with the drm maintainer tools today to try to apply
> the patch, with no luck.   I'll keep trying, and if I succeed, I'll
> push it.

Hi Eric,

unclear whether you want me to do the split or whether you are going
to (your last paragraph). Also I'm a bit unclear on the exact
requirements for the prefixes etc.

James