Re: [PATCH] Fix i915 drm regression on AOpen i915GMm-HFS motherboard

[Jean Delvare <khali@linux-fr.org>]

On Mon, 3 Jan 2011 12:26:07 -0800, Linus Torvalds wrote:
> [ related, but independent, issue ]
> 
> On Mon, Jan 3, 2011 at 11:59 AM, Chris Wilson <chris@chris-wilson.co.uk> wrote:
> >
> >                            That function currently requires
> > GMBUS to differentiate between a NAK and an IO error (bitbanging just
> > returns EREMOTEIO regardless, iirc).
> 
> Hmm. That sounds like something that would be worth fixing regardless
> and independently of this. I'd expect that a lot of users would care
> whether there was an actual protocol error or whether the command got
> a NAK. There's a big difference between "those lines don't seem to
> even be connected to anything" and "the other end didn't like us".
> 
> Even the comments in the bitbanging code seem to say that it should be
> returning ETIMEDOUT etc for when there is no answer (and the low-level
> "i2c_outb()" seems to do that), but then the code does seem to ignore
> all that information and turn all errors into EREMOTEIO.
> 
> Which sounds bogus.
> 
> Added Jean to the cc in case he has some input (or knows who we should
> bug about algo-bit.c). Also David Brownell, because he touched an
> error code in that file two and a half years ago, so he now owns it
> forever ;)

For the records, I did fix the bogus error codes in i2c-algo-bit in:

>From abc01b2718ee1d26e83c4c62c4b79806b3240ac7
From: Jean Delvare <khali@linux-fr.org>
Date: Sun, 30 Oct 2011 13:47:25 +0100
Subject: [PATCH] i2c-algo-bit: Return standard fault codes

Adjust i2c-algo-bit to return fault codes compliant with
Documentation/i2c/fault-codes, rather than the undocumented and
vague -EREMOTEIO.



R.I.P David...

-- 
Jean Delvare