Re: i2c: designware: unhandled interrupt on N100 lpss channel 0

Andy Shevchenko
2024-03-21T11:20:21Z

On Wed, Mar 20, 2024 at 10:26:06PM +0100, Heiner Kallweit wrote:
> On 20.03.2024 22:07, Andy Shevchenko wrote:
> > On Wed, Mar 20, 2024 at 09:21:34PM +0100, Heiner Kallweit wrote:
> >> On 20.03.2024 16:59, Andy Shevchenko wrote:
> >>> On Wed, Mar 20, 2024 at 03:56:29PM +0100, Heiner Kallweit wrote:

...

> >>> grep 0000001b /sys/kernel/debug/pinctrl/*/pins
> >>
> >> pin 3 (GPPC_B_3) 3:INTC1057:00 GPIO 0x80100102 0x0000001b 0x00000000 [LOCKED tx]
> >> pin 82 (GPP_F_7_EMMC_CMD) 135:INTC1057:00 GPIO 0x44000300 0x0000001b 0x00000000 [LOCKED full, ACPI]
> >> pin 182 (GPPC_C_13) 269:INTC1057:00 GPIO 0x44000300 0x0000001b 0x00000000 [LOCKED full, ACPI]
> >
> > I was not correct, the value to grep is '0000[0-3][0-9a-f]1b' as there pull
> > up/down can be enabled.
> >
> Result is the same
>
> > Nevertheless from the above the pin 3 is one that is enabled as GPIO input with
> > RTE 27 and direct IRQ. If it's a culprit, try to add in the pinctrl-intel.c at
> > the end of .probe:
> >
> > {
> > void __iomem *padcfg0;
> > u32 value;
> >
> > padcfg0 = intel_get_padcfg(pctrl, 3, PADCFG0);
> >
> > value = readl(padcfg0);
> > value |= PADCFG0_GPIOTXDIS;
> > value |= PADCFG0_GPIORXDIS;
> > writel(value, padcfg0);
> > }
> >
> > If it helps, it will show the BIOS bug (likely).
> >
> Wow, this indeed fixes the issue for me. Thanks a lot!

Wow! Glad to hear this.
(Side note, can you test the patch against idma64 I sent yesterday?
Tested-by tag will be appreciated!)

We may try to have the quirk in the kernel, but it might be (quite) tricky
(see the link below).

Can you share `acpidump -o n100-tables.dat` (the file) somewhere?
I would like to see if this pin is anyhow being mentioned in the DSDT.

> For my understanding: Shall we (kernel driver) rely on the BIOS to configure
> GPIO's properly?

Yes, but there are bugs.
You may look, e.g., https://bugzilla.kernel.org/show_bug.cgi?id=214749.

> Or better assume that GPIO's are in an unknown state on
> driver load and configure them for our needs?

It depends. But usually (> 99% cases) we rely on the firmware.

> IOW: If we assume that other systems may have similar issues, should
> "some driver" use e.g. the pinctrl API to configure relevant pins?

--
With Best Regards,
Andy Shevchenko