Re: [PATCH 2/2] hwmon: Allow to compile dell-smm-hwmon driver without /proc/i8k

[Guenter Roeck]

On 03/28/2015 03:00 PM, Pali RohÃr wrote:
> On Saturday 28 March 2015 13:54:51 Steven Honeyman wrote:
> > On 28 March 2015 at 11:04, Paul Bolle <pebolle@xxxxxxxxxx>
> wrote:
> > > On Sat, 2015-03-28 at 11:24 +0100, Pali RohÃr wrote:
> > > > --- a/drivers/hwmon/Kconfig
> > > > +++ b/drivers/hwmon/Kconfig
> > > > @@ -1703,6 +1703,17 @@ config SENSORS_ULTRA45
> > > >
> > > >          This driver provides support for the Ultra45
> > > >          workstation environmental sensors.
> > > >
> > > > +config SENSORS_DELL_SMM
> > > > +     tristate "Dell laptop SMM BIOS hwmon driver"
> > > > +     depends ON X86
> > >
> > > How did this past your testing?
> > >
> > > > +     ---help---
> > > > +       This hwmon driver adds support for reporting
> > > > temperature of different +       sensors and controls the
> > > > fans on Dell laptops via System Management +       Mode
> > > > provided by Dell BIOS.
> > > > +
> > > > +       When option I8K is also enabled this driver
> > > > provides legacy /proc/i8k +       userspace interface for
> > > > i8kutils package.
> > > > +
> >
> > It's working OK for me (after fixing the mistake pointed out
> > above).
> >
> > [Latitude e6540]
> > -----
> > coretemp-isa-0000
> > Adapter: ISA adapter
> > Physical id 0:  +53.0ÂC  (high = +84.0ÂC, crit = +100.0ÂC)
> > Core 0:         +51.0ÂC  (high = +84.0ÂC, crit = +100.0ÂC)
> > Core 1:         +53.0ÂC  (high = +84.0ÂC, crit = +100.0ÂC)
> >
> > i8k-virtual-0
> > Adapter: Virtual device
> > Processor Fan: 3171 RPM
> > CPU:            +52.0ÂC
> > Ambient:        +46.0ÂC
> > SODIMM:         +40.0ÂC
> > -----
> >
> > Ambient and SODIMM look swapped - but it's probably just
> > another Dell error. I really need to look at getting coreboot
> > on this thing.
>
> Both patches do not change any code. So there should not be any
> type swapped with or without my patch.
>
> Cpu type is requested via SMM in same way as it is doing old DOS
> executable. So there can be maybe problem in DELL SMM handler too
> or maybe just I did not understand correctly assembler dump of
> DOS executable...
>
> > On 28 March 2015 at 10:24, Pali RohÃr <pali.rohar@xxxxxxxxx>
> > wrote: ...
> >
> > >   config I8K
> > >
> > > -       tristate "Dell laptop support"
> > > -       select HWMON
> > > +       bool "Dell i8k legacy laptop support"
> > > +       select SENSORS_DELL_SMM
> >
> > ...
> >
> > > +config SENSORS_DELL_SMM
> > > +       tristate "Dell laptop SMM BIOS hwmon driver"
> >
> > The only change I'd suggest is not to change the tristate to
> > bool for I8K. Forcing that to bool means that
> > SENSORS_DELL_SMM can't be compiled as a module if the user
> > wishes to keep i8k hanging around "just in case". It'll
> > probably annoy distro kernel packagers too.
> >
> >
> > Thanks,
> > Steven
>
> My idea was:
>
> SENSORS_DELL_SMM enable/disable compilation of kernel driver
> (ether statically link into kernel image or as external module)
>
> CONFIG_I8K just enable /proc/i8k code in SENSORS_DELL_SMM -- no
> additional driver, just boolean switch which has effect only iff
> SENSORS_DELL_SMM is Y or M

Maybe that is the plan, but it is not what is happening.
I8K selects SENSORS_DELL_SMM, so a boolean I8K forces SENSORS_DELL_SMM
to be built into the kernel.

What you suggest would work if I8K would depend on SENSORS_DELL_SMM,
but then the symbols would not be backward-compatible.

Guenter

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