Re: [PATCH v5 2/2] hwmon: (acpi_power_meter) Ensure IPMI space handler is ready on Dell systems

[Guenter Roeck]

On 3/25/24 05:38, Andy Shevchenko wrote:
> On Wed, Mar 20, 2024 at 04:43:17PM +0800, Kai-Heng Feng wrote:
> > The following error can be observed at boot:
> > [    3.717920] ACPI Error: No handler for Region [SYSI] (00000000ab9e62c5) [IPMI] (20230628/evregion-130)
> > [    3.717928] ACPI Error: Region IPMI (ID=7) has no handler (20230628/exfldio-261)
> >
> > [    3.717936] No Local Variables are initialized for Method [_GHL]
> >
> > [    3.717938] No Arguments are initialized for method [_GHL]
> >
> > [    3.717940] ACPI Error: Aborting method \_SB.PMI0._GHL due to previous error (AE_NOT_EXIST) (20230628/psparse-529)
> > [    3.717949] ACPI Error: Aborting method \_SB.PMI0._PMC due to previous error (AE_NOT_EXIST) (20230628/psparse-529)
> > [    3.717957] ACPI: \_SB_.PMI0: _PMC evaluation failed: AE_NOT_EXIST
> >
> > On Dell systems several methods of acpi_power_meter access variables in
> > IPMI region [0], so wait until IPMI space handler is installed by
> > acpi_ipmi and also wait until SMI is selected to make the space handler
> > fully functional.
> >
> > Since the dependency is inside BIOS's ASL code and it's not
> > discoverable, so use this fixup is a hack to workaround BIOS issue.
>
> ...
>
> > +	if (dmi_match(DMI_SYS_VENDOR, "Dell Inc.")) {
> > +		ipi_device = acpi_dev_get_first_match_dev("IPI0001", NULL, -1);
> > +
> > +		if (ipi_device) {
> > +			if (acpi_wait_for_acpi_ipmi())
> > +				dev_warn(&device->dev, "Waiting for ACPI IPMI timeout");
> > +			acpi_dev_put(ipi_device);
> > +		}
>
> Can be written as
>
> 	if (dmi_match(DMI_SYS_VENDOR, "Dell Inc.")) {
> 		ipi_device = acpi_dev_get_first_match_dev("IPI0001", NULL, -1);
> 		if (ipi_device && acpi_wait_for_acpi_ipmi())
> 			dev_warn(&device->dev, "Waiting for ACPI IPMI timeout");
> 		acpi_dev_put(ipi_device);
>
> > +	}

Ah yes, acpi_dev_put() checks if the parameter is NULL. Good point.
I'll make that change, no need to resend.

Thanks,
Guenter