linux-kernel - Re: [PATCH] i8k: Add support for temperature sensor labels

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Message-ID: <2162660.rjBG3mszUn@xps13>
Date:	Sat, 29 Nov 2014 19:27:52 +0100
From:	Gabriele Mazzotta <gabriele.mzt@...il.com>
To:	Pali Rohár <pali.rohar@...il.com>
Cc:	Guenter Roeck <linux@...ck-us.net>, Arnd Bergmann <arnd@...db.de>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Steven Honeyman <stevenhoneyman@...il.com>,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] i8k: Add support for temperature sensor labels

On Saturday 29 November 2014 18:18:18 Pali Rohár wrote:
> On Saturday 29 November 2014 18:07:19 Gabriele Mazzotta wrote:
> > On Saturday 29 November 2014 17:09:35 Pali Rohár wrote:
> > > On Saturday 29 November 2014 17:04:07 Pali Rohár wrote:
> > > > This patch adds labels for temperature sensors if SMM
> > > > function with EAX register 0x11a3 reports it. These
> > > > informations was taken from DOS binary NBSVC.MDM.
> > > > 
> > > > Signed-off-by: Pali Rohár <pali.rohar@...il.com>
> > > > ---
> > > > 
> > > >  drivers/char/i8k.c |  110
> > > > 
> > > > +++++++++++++++++++++++++++++++++++++++++----------- 1
> > > > file changed, 88 insertions(+), 22 deletions(-)
> > > 
> > > I tested patch on Latitude E6440 and i8k CPU & GPU temps
> > > match intel coretemp & amd radeion temps.
> > > 
> > > But I would like if somebody with other Dell laptop can test
> > > if temperature labels are correct...
> > 
> > I tested it on my XPS13 9333, here what sensors outputs:
> > 
> > acpitz-virtual-0
> > Adapter: Virtual device
> > temp1:        +27.8°C  (crit = +105.0°C)
> > temp2:        +29.8°C  (crit = +105.0°C)
> > 
> > coretemp-isa-0000
> > Adapter: ISA adapter
> > Physical id 0:  +62.0°C  (high = +100.0°C, crit = +100.0°C)
> > Core 0:         +62.0°C  (high = +100.0°C, crit = +100.0°C)
> > Core 1:         +61.0°C  (high = +100.0°C, crit = +100.0°C)
> > 
> > i8k-virtual-0
> > Adapter: Virtual device
> > fan2:           0 RPM
> > CPU:          +62.0°C
> > Ambient:      +49.0°C
> > SODIMM:       +46.0°C
> > temp4:            N/A
> > 
> > CPU seems to be correct, but I can't say anything on Ambient
> > and SODIMM. temp4 is constantly equal to SODIMM without this
> > patch, so I'd say N/A is correct.
> > 
> > 
> > Gabriele
> 
> It is unknown for me how to directly read Ambient and SODIMM
> temperatures (without Dell SMM functions). So we can only trust
> Dell SMM that it reporting correct values and type is really
> Ambient and SODIMM.
> 
> And about temp4:
> 
> Label is not set when SMM function fails. Original DOS NBSVC.MDM
> just ignore all sensors for which SMM type function fails.
> 
> This patch should not disable any sensor, so if you previously
> had some value (<= 128°C) and now not, then there is some bug.
> 
> Can you test this patch?
> https://git.kernel.org/cgit/linux/kernel/git/gregkh/char-misc.git/comm
> it/?h=char-misc-testing&id=723493ca59c8d81fed3e7f261165fee493a29ffa
> 
> It is possible that same value is caused by incorrect use of
> prev[] array which should be fixed by above patch.
> 
> Can you test i8k with and without above patch?

I did some more tests. What I think is happening is that temp4_label
returns -22, so I sensors prints N/A without actually reading temp4_input.

I'm doing some tests to understand what's going on with temp4_input.
It reports the value of the last temp*_input I read. If I read it right
after I loaded i8k, I get an error (-22).

The same doesn't happen for temp3_label, which constantly returns -22.

I already had https://git.kernel.org/cgit/linux/kernel/git/gregkh/char-misc.git/commit/?h=char-misc-testing&id=723493ca59c8d81fed3e7f261165fee493a29ffa
applied. Without it, things seem not to change much.
I either get an error (-22) or some incorrect values (for now always
1000) when I read temp4_input right after i8k was loaded.
Once I read some other temp*_input, I always get the last value read.
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