Re: [PATCH v6 08/19] i2c: octeon: Enable High-Level Controller

From: Jan Glauber
Date: Thu Apr 21 2016 - 09:41:19 EST


On Wed, Apr 20, 2016 at 02:55:15PM -0700, David Daney wrote:
> On 04/20/2016 02:43 PM, Wolfram Sang wrote:
> >On Mon, Apr 11, 2016 at 05:28:39PM +0200, Jan Glauber wrote:
> [...]
> >>+ */
> >>+static int octeon_i2c_hlc_wait(struct octeon_i2c *i2c)
> >>+{
> >>+ int time_left;
> >>+
> >>+ octeon_i2c_hlc_int_enable(i2c);
> >>+ time_left = wait_event_interruptible_timeout(i2c->queue,
> >>+ octeon_i2c_hlc_test_ready(i2c),
> >>+ i2c->adap.timeout);
> >
> >Have you tested signal handling thoroughly? Most driver dropped the
> >_interruptible after a while. Mostly they found out that the state
> >machine of the interrupt handler couldn't gracefully deal with it and
> >nobody really needed the interruptible. Just saying.
>
> Good point. We know that exiting with a signal leaves us in an
> undefined state.
>
> We will have to think on this point.

I think we should just drop the _interruptible_ and use
wait_event_timeout. The same is already used in the octeon_i2c_wait().
The 2ms timeout should not hurt anyone.

> >
> >>+ octeon_i2c_int_disable(i2c);
> >>+ if (!time_left) {
> >>+ octeon_i2c_hlc_int_clear(i2c);
> >>+ dev_dbg(i2c->dev, "%s: timeout\n", __func__);
> >>+ return -ETIMEDOUT;
> >>+ }
> >>+
> >>+ if (time_left < 0) {
> >>+ dev_dbg(i2c->dev, "%s: wait interrupted\n", __func__);
> >>+ return time_left;
> >>+ }
> >>+ return 0;
> >>+}
> >
> >Drop the debug messages?
> >
> >I can't say much about the HW details, of course. Didn't spot anything
> >suspicious there.
> >