Messages in this thread | | | Date | Tue, 9 Jan 2024 07:23:40 -0800 | Subject | Re: [PATCH v4 2/2] hwmon: (acpi_power_meter) Ensure IPMI space handler is ready on Dell systems | From | Guenter Roeck <> |
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On 1/8/24 20:12, 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. > > [0] https://www.dell.com/support/manuals/en-us/redhat-enterprise-linux-v8.0/rhel8_rn_pub/advanced-configuration-and-power-interface-acpi-error-messages-displayed-in-dmesg?guid=guid-0d5ae482-1977-42cf-b417-3ed5c3f5ee62 > > Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com> > --- > v4: > - No change. > > v3: > - Use helper. > - Use return value to print warning message. > > v2: > - Use completion instead of request_module(). > > drivers/hwmon/acpi_power_meter.c | 6 ++++++ > 1 file changed, 6 insertions(+) > > diff --git a/drivers/hwmon/acpi_power_meter.c b/drivers/hwmon/acpi_power_meter.c > index 703666b95bf4..33fb9626633d 100644 > --- a/drivers/hwmon/acpi_power_meter.c > +++ b/drivers/hwmon/acpi_power_meter.c > @@ -883,6 +883,12 @@ static int acpi_power_meter_add(struct acpi_device *device) > strcpy(acpi_device_class(device), ACPI_POWER_METER_CLASS); > device->driver_data = resource; > > + if (dmi_match(DMI_SYS_VENDOR, "Dell Inc.") && > + acpi_dev_get_first_match_dev("IPI0001", NULL, -1)) { > + if (acpi_wait_for_acpi_ipmi()) > + dev_warn(&device->dev, "Waiting for ACPI IPMI timeout"); > + } > +
What a hack :-(.
This needs a comment in the driver explaining the rationale for this change, and also a comment explaining why, for example, using late_initcall() does not help.
If CONFIG_IPMI_SI=n, acpi_wait_for_acpi_ipmi() will return 0, indicating success. I can only imagine that this will result in a failure since the whole point of this code is to wait until that driver is loaded. Please explain how and why the code works with CONFIG_IPMI_SI=n. Similar, if the function returns an error, I can not imagine how it would make sense to instantiate the driver. If it does make sense to continue in this situation, a comment is needed in the code describing the rationale.
Third, the new symbol is declared with CONFIG_ACPI, but defined with CONFIG_IPMI_SI. I can not imagine how this would compile with CONFIG_ACPI=y and CONFIG_IPMI_SI={m,n} and/or CONFIG_ACPI_IPMI={m,n}.
On top of that, IPMI_SI and ACPI_IPMI are is tristate, as is SENSORS_ACPI_POWER. This means that SENSORS_ACPI_POWER=y combined with CONFIG_IPMI_SI={m,n} or CONFIG_ACPI_IPMI={m,n} will result in a compile failure.
Please make sure that this code compiles with all possible symbol combinations.
Thanks, Guenter
> res = read_capabilities(resource); > if (res) > goto exit_free;
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