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Subject: Re: i2c-powermac fails
From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
To: Jean Delvare <khali@linux-fr.org>
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Date: Thu, 15 Oct 2009 08:26:15 +1100
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Cc: Paul Mackerras <paulus@samba.org>, Tim Shepard <shep@alum.mit.edu>,
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On Wed, 2009-10-14 at 23:02 +0200, Jean Delvare wrote:
> Hi all,
> 
> On Tue, 13 Oct 2009 11:49:48 +0200, Jean Delvare wrote:
> > I2C bus being setup too fast sounds more likely. It might be worth
> > adding an arbitrary delay after initialization, just to see if it
> > helps. Not sure where though, as I'm not familiar with the Powermac
> > initialization steps. Maybe right before i2c_add_adapter() in
> > i2c_powermac_probe?
> 
> Tim, can you please give a try to this patch? Obviously your machine
> will take 5 additional seconds to boot, and this isn't meant as a real
> fix, but if it helps, this will be an interesting hint for further
> debugging attempts.

Oh, I was actually thinking about the frequency of the I2C clock :-)

Cheers,
Ben.

> --- kernel32.orig/drivers/macintosh/therm_adt746x.c
> +++ kernel32/drivers/macintosh/therm_adt746x.c
> @@ -380,6 +380,7 @@ static int probe_thermostat(struct i2c_c
>  	if (thermostat)
>  		return 0;
>  
> +	msleep(5000);
>  	th = kzalloc(sizeof(struct thermostat), GFP_KERNEL);
>  	if (!th)
>  		return -ENOMEM;
> 
>