Date:	Sat, 28 Mar 2015 23:33:46 +0100
From:	Pali Rohár <pali.rohar@...il.com>
To:	Steven Honeyman <stevenhoneyman@...il.com>
Cc:	Paul Bolle <pebolle@...cali.nl>,
	Guenter Roeck <linux@...ck-us.net>,
	Arnd Bergmann <arnd@...db.de>,
	"Greg Kroah-Hartman" <gregkh@...uxfoundation.org>,
	Jean Delvare <jdelvare@...e.de>,
	Valdis Kletnieks <Valdis.Kletnieks@...edu>,
	Jochen Eisinger <jochen@...guin-breeder.org>,
	Gabriele Mazzotta <gabriele.mzt@...il.com>,
	linux-kernel@...r.kernel.org, lm-sensors@...sensors.org
Subject: Re: [PATCH 2/2] hwmon: Allow to compile dell-smm-hwmon driver without /proc/i8k

On Saturday 28 March 2015 23:19:04 Steven Honeyman wrote:
> On 28 March 2015 at 22:00, Pali Rohár <pali.rohar@...il.com>
> wrote:
> > On Saturday 28 March 2015 13:54:51 Steven Honeyman wrote:
> >> i8k-virtual-0
> >> Adapter: Virtual device
> >> Processor Fan: 3171 RPM
> >> CPU:            +52.0°C
> >> Ambient:        +46.0°C
> >> SODIMM:         +40.0°C
> >> -----
> >> 
> >> 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...
> 
> Is there some way that I can find out for you? I've got a
> Windows partition somewhere, or DOS boot disk should be easy
> enough if this program works on new hardware.
> If I knew where the sensors were placed I could cool one of
> them.
> 

Maybe DOS executable is just too old... and need to use new one. 
I extracted diagnostic application from BIOS package (EFI binary 
which show temperature in BIOS) for my laptop, but decoding 
instructions of this big graphic binary is beyond my power. But 
it looks like it calls same SMM inb/outb calls, so SMM code in 
BIOS handler was not changed.

So if you want to fix this problem, next step is to disassemble 
or understand new modern EFI diag binary...

I think it would be better to locate on which bus are sensors 
connected (smbus? isa? pci?), find out HW chips and wrote native 
kernel drivers for them...

I scanned smbus (intel controller connected on pci) on my E6440 
but there is no additional/unknown device. I have no idea where 
else could be sensor device connected and accessible (from SMM or 
kernel mode).

> On 28 March 2015 at 22:04, Pali Rohár <pali.rohar@...il.com>
> wrote:
> > I think that setting CONFIG_I8K to tristate (Y/M/N) does not
> > make sense... CONFIG_I8K just control if /proc/i8k will be
> > compiled into dell-smm-hwmon or not.
> 
> Try and select dell-smm-hwmon as a module, with i8k enabled as
> well...
> 

Got it.

> On 28 March 2015 at 22:06, Paul Bolle <pebolle@...cali.nl>
> wrote:
> > On Sat, 2015-03-28 at 22:55 +0100, Pali Rohár wrote:
> >> I have tested compilation only with out of tree make
> >> command with manual CONFIG_SENSORS_DELL_SMM and CONFIG_I8K
> >> options.
> > 
> > Not sure what you mean here. I can't get things past this
> > error:
> >     drivers/hwmon/Kconfig:1721: syntax error
> >     drivers/hwmon/Kconfig:1720: invalid option
> 
> --- a/drivers/hwmon/Kconfig
> +++ b/drivers/hwmon/Kconfig
> @@ -1705,8 +1705,8 @@
> 
>  config SENSORS_DELL_SMM
>      tristate "Dell laptop SMM BIOS hwmon driver"
> -    depends ON X86
> -    ---help---
> +    depends on X86
> +    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.

-- 
Pali Rohár
pali.rohar@...il.com

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