On Thu, 15 Oct 2009 16:05:13 +0200, Jean Delvare wrote:

On Thu, 15 Oct 2009 22:19:19 +1100, Benjamin Herrenschmidt wrote:

quoted

On Thu, 2009-10-15 at 12:49 +0200, Jean Delvare wrote:

quoted

Oh. Well, if that was the case, we would see errors all the time, not
just during initialization, right? Or does the I2C clock frequency
change over time somehow?

No but maybe we are a bit on the "limit" of the device and some
registers take long to respond than others ?

Unlikely. The ADT7460 can run at I2C clock rates up to 400 kHz while
the Keywest I2C runs at 25, 50 or 100 kHz if I read the code properly.
I don't know what exact speed is used on Tim's system, apparently it is
read from the hardware in the device tree directly?

We could have low_i2c.c log the I2C clock frequency and/or try to force
the lowest speed (25 kHz) and see if it helps, but I very much doubt
it. And I'd rather wait for Tim to report the result with my last patch
first.

Ben, wouldn't this recent patch of yours be worth testing too?

http://git.kernel.org/?p=linux/kernel/git/torvalds/linux-2.6.git;a=commitdiff;h=11a50873ef2b3c1c3fe99a661c22c08f35d93553

If it solves problems at resume time, I guess it might also solve
problems at boot time?

-- 
Jean Delvare