From mboxrd@z Thu Jan  1 00:00:00 1970
From: Daniel Vetter <daniel@ffwll.ch>
Subject: Re: [DVO][PATCH] drm/i915: Fall back to bit banging mode for DVO
	transmitter detection
Date: Fri, 19 Apr 2013 16:31:37 +0200
Message-ID: <20130419143137.GV6169@phenom.ffwll.local>
References: <5171034E.1020204@elsoft.ch>
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To: =?iso-8859-1?Q?=22David_M=FCller_=28ELSOFT_AG=29=22?= <d.mueller@elsoft.ch>
Cc: intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org
List-Id: dri-devel@lists.freedesktop.org

On Fri, Apr 19, 2013 at 12:54:00PM +0200, "David M=FCller (ELSOFT AG)" wrot=
e:
> Daniel Vetter wrote:
> > On Fri, Apr 19, 2013 at 10:41:50AM +0200, "David M=FCller (ELSOFT AG)" =
wrote:
> >> +		/* GMBUS NAK handling seems to be unstable, hence let the
> >> +		 * transmitter detection run in bit banging mode for now.
> >> +		 */
> >> +		intel_gmbus_force_bit(i2c, true);
> >> +
> >> +		dvoinit =3D dvo->dev_ops->init(&intel_dvo->dev, i2c);
> >> +
> >> +		intel_gmbus_force_bit(i2c, false);
> > =

> > Shouldn't we keep the dvo i2c line in bit-banging mode always, i.e.
> > restore gmbus mode only when dvo init failed?
> > =

> > I suspect that for fickle hw not just init will fail ...
> =

> As far as i can tell, the critical part is the NAK handling.

Ok, I've merged the patch for 3.10 with cc: stable.

Thanks, Daniel
-- =

Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch