Re: [PATCH v3] hwmon: add HP WMI Sensors driver

[Armin Wolf]

Am 27.04.23 um 09:37 schrieb James Seo:

> On Wed, Apr 26, 2023 at 09:35:33PM +0200, Armin Wolf wrote:
> > Am 26.04.23 um 15:16 schrieb James Seo:
> >
> > > On Mon, Apr 24, 2023 at 11:13:36PM +0200, Armin Wolf wrote:
> > > > Am 24.04.23 um 12:05 schrieb James Seo:
> > > >
> > > > > +	for (i = 0; i < HP_WMI_MAX_INSTANCES; i++, pevents++) {
> > > > Hi,
> > > >
> > > > the WMI driver core already knows how many instances of a given WMI object are available.
> > > > Unfortunately, this information is currently unavailable to drivers. Would it be convenient
> > > > for you to access this information? I could try to implement such a function if needed.
> > > >
> > > > > +	for (i = 0; i < HP_WMI_MAX_INSTANCES; i++, info++) {
> > > > Same as above.
> > > Hello,
> > >
> > > Having the WMI object instance count wouldn't make much difference to
> > > me for now. The driver has to iterate through all instances during
> > > init anyway. If I were forced to accommodate 50+ sensors, I'd rewrite
> > > some things and I think I'd want such a function then, but I picked
> > > the current arbitrary limit of 32 because even that seems unlikely.
> > >
> > > So, maybe don't worry about it unless you want to. Or am I missing
> > > something?
> > Hi,
> >
> > i already have a experimental patch available which adds such a function.
> > If you could test this patch to see if it works, then i could submit it upstream
> > where other drivers could profit from being able to know the number of
> > WMI object instances.
> Both your proposed functions worked as expected.
>
> > Your driver could also profit from such a function, as it could optimize the amount
> > of memory allocated to store WMI object data.
> I suppose I might as well. I assume I'm supposed to wait until your
> new functions are merged before making changes that rely on them?

I think you can submit this driver as-is and provide a follow-up patch once
the changes are merged.

> > The current instance discovery algorithm
> > (using a for-loop and break on error) also has a potential issue: when a single WMI call
> > fails for some reason (ACPI error, ...), all following WMI instances are being ignored.
> This is the intended behavior for now, on the assumption that a real
> ACPI failure probably indicates that the system has bigger problems.
> I do have vague plans to make the driver more tolerant of failure to
> retrieve or validate instances, but haven't decided anything yet.
>
> Regards,
>
> James

Ok.

Armin Wolf