Hi,
pe, 2012-10-12 kello 14:46 +0000, Strashko, Grygorii kirjoitti:
> Hi Kevin,
>
> yep, [1] is the same fix - thanks.
>
> Hi Kalle,
>
> i've applied these changes and PM runtime fix on top of
> git://git.kernel.org/pub/scm/linux/kernel/git/tmlind/linux-omap.git
> (omap2plus_defconfig)
> Could you check it with your use case, pls? (just to be sure that idea is
> right)
Odd, it's not working. I'll add some debug prints to see what happens
there.
- Kalle
>
> diff --git a/drivers/i2c/busses/i2c-omap.c b/drivers/i2c/busses/i2c-omap.c
> index a0e49f6..cb09e20 100644
> --- a/drivers/i2c/busses/i2c-omap.c
> +++ b/drivers/i2c/busses/i2c-omap.c
> @@ -586,6 +586,9 @@ omap_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg
> msgs[], int num)
> if (IS_ERR_VALUE(r))
> goto out;
>
> + /* We have the bus, enable IRQ */
> + enable_irq(dev->irq);
> +
> r = omap_i2c_wait_for_bb(dev);
> if (r < 0)
> goto out;
> @@ -606,6 +609,7 @@ omap_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg
> msgs[], int num)
> r = num;
>
> omap_i2c_wait_for_bb(dev);
> + disable_irq(dev->irq);
> out:
> pm_runtime_put(dev->dev);
> return r;
> @@ -1060,6 +1064,9 @@ omap_i2c_probe(struct platform_device *pdev)
>
> omap_i2c_isr;
> r = request_irq(dev->irq, isr, IRQF_NO_SUSPEND, pdev->name, dev);
>
> + /* We enable IRQ only when request for I2C from master */
> + disable_irq(dev->irq);
> +
> if (r) {
> dev_err(dev->dev, "failure requesting irq %i\n", dev->irq);
> goto err_unuse_clocks;
> @@ -1182,7 +1189,23 @@ static int omap_i2c_runtime_resume(struct device *dev)
> }
> #endif /* CONFIG_PM_RUNTIME */
>
> +static int omap_i2c_suspend(struct device *dev)
> +{
> + int ret;
> +
> + /*
> + * Enable I2C device, so it will be accessible during
> + * later stages of suspending when device Runtime PM is disabled.
> + * I2C device will be turned off at "noirq" suspend stage.
> + */
> + ret = pm_runtime_resume(dev);
> + if (ret < 0)
> + return ret;
> + return 0;
> +}
> +
> static struct dev_pm_ops omap_i2c_pm_ops = {
> + SET_SYSTEM_SLEEP_PM_OPS(omap_i2c_suspend, NULL)
> SET_RUNTIME_PM_OPS(omap_i2c_runtime_suspend,
> omap_i2c_runtime_resume, NULL)
> };
>
> - Grygorii
> ________________________________________
> From: Kevin Hilman [[email protected]]
> Sent: Friday, October 12, 2012 5:34 PM
> To: Strashko, Grygorii
> Cc: Kalle Jokiniemi; [email protected]; [email protected];
> [email protected]; [email protected]; [email protected]; Datta,
> Shubhrajyoti; Kankroliwala, Huzefa
> Subject: Re: [PATCH v3] ARM: OMAP: i2c: fix interrupt flood during resume
>
> "Strashko, Grygorii" <[email protected]> writes:
>
> > Hi All,
> >
> > Sorry, for the late reply.
> > + CC Huzefa Kankroliwala - who is I2C driver owner on Android Kernel 3.4.
>
> Hi Grygorii, thanks for reviewing. I was hoping you would have some
> ideas here as this was sounding familiar to something you had
> mentioned elsewhere.
>
> > Regarding this patch - from my point of view, it fixes corner case and not
> > an issue in general.
> > Let take a look on resume sequence:
> > - platform resume
> > - syscore resume
> > - resume_noirq
> > - enable IRQs - resume_device_irqs()
> > |- at this point IRQ handler will be invoked if IRQ state is
> > IRQS_PENDING.
> > |- so, the I2C device IRQ handler may be called at time when I2C
> > adapter IRQ is still disabled and, as result, the I2C device IRQ-handler
> > may fail. (I2C device and I2C adapter may use different physical IRQ lines)
> > - resume_late
> > |- enable I2C bus IRQ
> >
> > Possibly, the better way is to enable/disable I2C bus IRQ when needed - in
> > our case in omap_i2c_xfer().
> > We use such approach in Android kernel 3.4
> > (http://git.omapzoom.org/?p=kernel/omap.git;a=commitdiff;h=1445a4d3b587c164bd30d108b61760aaaa07365e)
>
> I agree, that should work and cover the cases where I2C is used by other
> processors also. Shubhrajyoti already posted something similar[1] but
> it needed some rework (comments from Russell and myself.)
>
> Huzefa, Shubhrajyoti, who can rework this idea for the upstream and/or
> follow up with the earlier patch[1]?
>
> Wolfram, I guess for now lets hold off on $SUBJECT patch. Seems we can
> come up with a broader solution. Thanks.
>
> Kevin
>
> [1]
> http://lists.infradead.org/pipermail/linux-arm-kernel/2012-October/124427.html
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