Re: [PATCHv3] gpio: gpio-omap: Fix lost edge wake-up interrupts

[Linus Walleij <linus.walleij@xxxxxxxxxx>]

On Wed, Jun 12, 2019 at 8:34 AM Tony Lindgren <tony@xxxxxxxxxxx> wrote:

> If an edge interrupt triggers while entering idle just before we save
> GPIO datain register to saved_datain, the triggered GPIO will not be
> noticed on wake-up. This is because the saved_datain and GPIO datain
> are the same on wake-up in omap_gpio_unidle(). Let's fix this by
> ignoring any pending edge interrupts for saved_datain.
>
> This issue affects only idle states where the GPIO module internal
> wake-up path is operational. For deeper idle states where the GPIO
> module gets powered off, Linux generic wakeirqs must be used for
> the padconf wake-up events with pinctrl-single driver. For examples,
> please see "interrupts-extended" dts usage in many drivers.
>
> This issue can be somewhat easily reproduced by pinging an idle system
> with smsc911x Ethernet interface configured IRQ_TYPE_EDGE_FALLING. At
> some point the smsc911x interrupts will just stop triggering. Also if
> WLCORE WLAN is used with EDGE interrupt like it's documentation specifies,
> we can see lost interrupts without this patch.
>
> Note that in the long run we may be able to cancel entering idle by
> returning an error in gpio_omap_cpu_notifier() on pending interrupts.
> But let's fix the bug first.
>
> Also note that because of the recent clean-up efforts this patch does
> not apply directly to older kernels. This does fix a long term issue
> though, and can be backported as needed.
>
> Cc: Aaro Koskinen <aaro.koskinen@xxxxxx>
> Cc: Grygorii Strashko <grygorii.strashko@xxxxxx>
> Cc: Keerthy <j-keerthy@xxxxxx>
> Cc: Ladislav Michl <ladis@xxxxxxxxxxxxxx>
> Cc: Peter Ujfalusi <peter.ujfalusi@xxxxxx>
> Cc: Russell King <rmk+kernel@xxxxxxxxxxxxxxx>
> Cc: Tero Kristo <t-kristo@xxxxxx>
> Signed-off-by: Tony Lindgren <tony@xxxxxxxxxxx>

Patch applied.

Let's see if this nails it.

Yours,
Linus Walleij