Re: [PATCH 1/1] pinctrl: add IRQF_EARLY_RESUME flags with gpio irq for elan touchpad.

[Andy Shevchenko <andriy.shevchenko@intel.com>]

On Mon, Nov 23, 2020 at 01:46:50PM +0100, Hans de Goede wrote:
> On 11/12/20 2:52 PM, Andy Shevchenko wrote:
> > 
> > +Cc: Hans.
> > 
> > I can't speak for AMD, but I think it may be useful for Intel pin control.
> > However, I didn't check what may be the side effects of this change and neither
> > contributor answered to my comments...
> 
> AFAICT setting IRQF_EARLY_RESUME causes it to not be resumed during
> normal IRQ resuming, but earlier during the syscore_resume() call.
> 
> There are 2 problems with this:
> 
> 1. When using S3 suspend syscore_resume() runs before any device
> suspend handlers, so any state restoring which the GPIO controller's
> resume handler is doing has not been done yet. While esp. after
> S3 suspend the restoring may be important (s2idle suspend should
> not touch the GPIO registers contents).
> 
> 2. When using S2idle suspend syscore_resume() *never* runs, and
> IRQs marked with IRQF_EARLY_RESUME are skipped during the normal
> IRQ resume phase, so these IRQs will never be resumed.
> 
> Also IRQF_EARLY_RESUME is used almost no where:

Yes, I also noticed this.

> [hans@x1 linux]$ ack -l IRQF_EARLY_RESUME drivers
> drivers/xen/events/events_base.c
> drivers/rtc/rtc-sc27xx.c
> drivers/mfd/twl4030-irq.c
> 
> Which is probably why we have not yet hit the s2idle issue with it.
> 
> So this all in all seems like a bad idea, and we need to better root
> cause the issue with these Elan touchpads and fix the actual issue.

Thanks! That is useful to know.

> > So, just heads up.
> > 
> > On Fri, Apr 24, 2020 at 05:12:01PM +0800, caizhaopeng@uniontech.com wrote:
> >> From: Caicai <caizhaopeng@uniontech.com>
> >>
> >> I had tested two Notebook machines, the Intel i5(or amd ryzen)
> >> with elan touchpad, and there's a probability that the touchpad
> >> won't work after going to the S3/S4 to wake up, that it would
> >> appear no more than 15 times. I found that there's no interrupt
> >> to check for /proc/interrupt. It was found that the gpio
> >> interrupt of i2c was also not on top. By adding the gpio
> >> interrupt flags with IRQF_EARLY_RESUME, now the touchpad tested
> >> 200 + times works well.

-- 
With Best Regards,
Andy Shevchenko