[PATCH] i2c: samsung: resume race fix

[Olof Johansson]

2013/1/24 Wolfram Sang <w.sang at pengutronix.de>

> On Wed, Nov 07, 2012 at 11:44:37AM +0100, Jean Delvare wrote:
> > On Wed, 07 Nov 2012 15:58:26 +0530, Naveen Krishna Chatradhi wrote:
> > > Don't unmark the device as suspended until after it's been re-setup.
> > >
> > > The main race would be w.r.t. an i2c driver that gets resumed at the
> same
> > > time (asyncronously), that is allowed to do a transfer since suspended
> > > is set to 0 before reinit, but really should have seen the -EIO return
> > > instead.
> >
> > I thought that the suspend order was children first and the resume
> > order was parent first?
>
> Same here, why does it not work this way?
>

Sorry for being quiet on this so far, I didn't notice the controversy until
now.

This is actually about half of what the original fix was (which I wrote,
thus my signed-off-by). The original one was related to us having the GPIO
handshake for a shared bus (see separate discussions on how that should be
upstreamed, and the work on that). For reference, that patch is at:
https://gerrit.chromium.org/gerrit/#/c/28126/1/drivers/i2c/busses/i2c-s3c2410.c
.

So, I'm not sure that this patch is really needed. The significant part of
the original one was the move of our internal s3c24xx_i2c_dt_gpio_free()
below setting suspended = 1. Upstream implementation of the same
functionality will be implemented differently, most likely.


-Olof
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