Hi Corey, On Wed, Jan 10, 2024 at 7:52 AM Corey Minyard <minyard@xxxxxxx> wrote: > > On Tue, Jan 09, 2024 at 02:32:41PM -0800, Guenter Roeck wrote: > > On 1/9/24 13:28, Corey Minyard wrote: > > > On Tue, Jan 09, 2024 at 07:23:40AM -0800, Guenter Roeck wrote: > > > > 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@xxxxxxxxxxxxx> > > > > > --- > > > > > 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. > > > > > > I'm trying to figure out where CONFIG_IPMI_SI comes in here. It's > > > nowhere in these patches or in drivers/acpi. ACPI_IPMI depends on > > > IPMI_HANDLER, but that's all I found. However, ACPI_IPMI can be "m" as > > > you mention and SENSOR_ACPI_POWER is only under the ACPI config, which > > > is a problem. > > > > > > > The patch above is looking for IPI0001, which is instantiated in > > > > drivers/char/ipmi/ipmi_si_platform.c: { "IPI0001", 0 }, > > drivers/char/ipmi/ipmi_ssif.c: { "IPI0001", 0 }, > > > > Are you saying that the above code doesn't depend on it ? In that case, > > why does it need to check for the IPI0001 device in the first place ? > > > > That will need another comment/explanation in the code because people > > (or maybe dummies) like me won't understand the non-dependency (i.e., > > the need to look for IPI0001 but not requiring the associated code). > > > > More specifically, unless I really don't understand the acpi code, > > acpi_dev_get_first_match_dev() will return NULL if there is no matching > > device. In that case, the above code won't call acpi_wait_for_acpi_ipmi(). > > Fine, but why would this driver have to wait for ipmi if and only if there > > is a device (and thus a driver) for IPI0001 ? > > Honestly, I don't really understand the acpi code that well, either. > What I think it's saying is that if IPI0001 is present in the ACPI > tables (there is an acpi_device present), then wait for the driver to > get loaded. It could be IPMI_SI or IPMI_SSIF, but there's no direct > connection between this code and the low-level IPMI driver. I don't > think it forces the driver to load, at least not from what I can tell. The dependency isn't discoverable at software level. It's all in the BIOS' ASL > > And another bug. From the description of acpi_dev_get_first_match_dev(): > The caller is responsible for invoking acpi_dev_put() on the returned device. Sure. I'll fix it in next revision. > > As you said, this is a big hack. There must be a better way. Unfortunately I really can't find a better alternative if the dependency isn't declared anywhere. Kai-Heng > > -corey > > > > > Thanks, > > Guenter > > > > > I do think there are other issues with this patch, though. The IPMI > > > handler code decouples the user from the driver from a dependency point > > > of view. It seems to be fairly common to see IPMI_HANDLER and > > > ACPI_IPMI as "y" and IPMI_SI (and IPMI_SSIF, and others) as "m". That > > > means this code will run but will wait for the IPMI device to appear, > > > which may not be until the module gets loaded, which may be far more > > > than 2 seconds later. > > > > > > I'm not quite sure how to fix this. Really, the add call for this > > > driver shouldn't be called until the IPMI device is present. Doesn't > > > ACPI have mechanisms to handle this sort of thing? If so, the hack may > > > need to be in the handling of that ACPI data (this field is not there > > > but should be), not here, which as Guenter says, is a big hack. > > > > > > -corey > > > > > > > > > > > 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; > > > > > > > > > > > > > > >
