Re: Handling <Ctrl-c> like events in 's_power' implementation when wehave a GPIO controlling the sensor CE

From: Linus Walleij
Date: Wed Feb 01 2012 - 07:29:37 EST


On Wed, Feb 1, 2012 at 6:01 AM, Bhupesh SHARMA <bhupesh.sharma@xxxxxx> wrote:

> Our board has a I2C controlled camera sensor whose Chip Enable (CE)
> pin is driven via a GPIO. This GPIO is made available by a I2C-to-GPIO
> expander chip (STMPE801, see user manual [1])
(...)
> the I2C controller driver
> (we use the standard SYNOPSYS designware device driver present in mainline,
> see [3]) returns -ERESTARTSYS in response to the write command we had requested
> for putting the sensor to power-off state (as it has received the <ctrl-c> kill
> signal).

So what happens if you go into the I2C driver and replace all things
that look like this:

ret = wait_for_completion_interruptible_timeout(&dev->cmd_complete, HZ);

With this:
ret = wait_for_completion_timeout(&dev->cmd_complete, HZ);

(Non-interruptible.)

This is usually the problem.

Yours,
Linus Walleij
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