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Date: Fri, 24 Oct 2008 20:25:33 +0200 (CEST)
From: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
To: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Subject: Re: [PATCH] fix i2c on PPC linkstation / kurobox machines
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On Fri, 24 Oct 2008, Benjamin Herrenschmidt wrote:

> On Fri, 2008-10-24 at 01:05 +0200, Guennadi Liakhovetski wrote:
> > i2c is broken on linkstation / kurobox machines since at least 2.6.27. Fix 
> > it. Also remove CONFIG_SERIAL_OF_PLATFORM, which, if enabled, breaks the 
> > serial console after the "console handover: boot [udbg0] -> real [ttyS1]" 
> > message.
> > 
> > Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
> 
> You may want to use udbg_printf() to track down what's up. There's some
> fishy code there indeed, what happens is that the legacy serial code
> creates a platform device at boot time. Then, the of_serial attaches to
> the device node for the same device and tries to register it. It's
> supposed to "detect" that it's the same device but yeah, it may be
> buggy, I've seen problems with it in the past, among others, I think it
> can lose some state.
> 
> In the meantime, removing SERIAL_OF_PLATFORM is a good solution.
> 
> Ben.

I think, this needs an acked-by for -stable.

Thanks
Guennadi
---
Guennadi Liakhovetski, Ph.D.
Freelance Open-Source Software Developer