Message-ID: <485E5238.6040801@keyaccess.nl>
Date: Sun, 22 Jun 2008 15:23:04 +0200
From: Rene Herman <rene.herman@keyaccess.nl>
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To: Hans de Goede <j.w.r.degoede@hhs.nl>
CC: "Mark M. Hoffman" <mhoffman@lightlink.com>,
       Linux Kernel <linux-kernel@vger.kernel.org>, lm-sensors@lm-sensors.org,
       Jean Delvare <khali@linux-fr.org>, Zhang Rui <rui.zhang@intel.com>,
       linux-acpi@vger.kernel.org
Subject: Re: [REGRESSION, ABI] Re: [lm-sensors] LMSENSORS: 2.6.26-rc, enabling
 ACPI Termal Zone support costs sensors
References: <485DA11C.7050906@keyaccess.nl> <485DFF35.6080008@hhs.nl> <485E505F.8010306@keyaccess.nl>
In-Reply-To: <485E505F.8010306@keyaccess.nl>
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On 22-06-08 15:15, Rene Herman wrote:

> On 22-06-08 09:28, Hans de Goede wrote:
> 
> This is an ABI breakage issue and an unfortunate one at that:
> 
>> Rene Herman wrote:
> 
>>> On 2.6.26-rc and perhaps earlier, when I enable the ACPI Thermal Zone 
>>> support (CONFIG_ACPI_THERMAL) I see in dmesg:
> 
> Note, 2.6.25-rc7 works fine with it enabled.

Sorry -- 2.6.25.7 I mean.

>>> ACPI: LNXTHERM:01 is registered as thermal_zone0
>>> ACPI: Thermal Zone [THRM] (56 C)
>>>
>>> My /sys/class/hwmon/hwmon0 (a W83782D chip) becomes hwmon1, there's a 
>>> new /sys/class/hwmon/hwmon0 and "sensors -s" craps out with:
>>>
>>> # sensors -s
>>> Can't access procfs/sysfs file
>>> Kernel interface access error
>>> For 2.6 kernels, make sure you have mounted sysfs and libsensors
>>> was compiled with sysfs support!
>>>
>>> # sensors --version
>>> sensors version 2.10.6 with libsensors version 2.10.6
>>>
>>> This is the slackware 12.1 (recent) standard version. What's wrong?
>>>
>>> In case it's useful, my /etc/sensors.conf is at:
>>>
>>> http://members.home.nl/rene.herman/sensors.conf
>>
>> I'm pretty sure this caused by your lm_sensors using space being to 
>> old to support the new thermalzone stuff. You need atleast 3.0.2 to 
>> support the thermalzone driver.
> 
> I see. I was about to mark this up as Volkerding doing his usual "if it 
> has a lower version number it must be better" thing but in this case it 
> seems it's hwmon or ACPI which is to blame.
> 
> Firstly -- with CONFIG_ACPI_THERMAL selected my sensors work fine on 
> 2.6.25-rc7 with the above 2.10.6 lm_sensors userspace. Now, with 
> 2.6.26-rc (*) they do not as per above.
> 
> This is ABI breakage. I wouldn't care if my older lm_sensors userspace 
> couldn't handle the ACPI Thermal Zone, but I do care that even having it 
> breaks my other sensors; especially given the CONFIG_ACPI_THERMAL help 
> text which can not be read as recommending to disable it:
> 
>   This driver adds support for ACPI thermal zones.  Most mobile and
>   some desktop systems support ACPI thermal zones.  It is HIGHLY
>   recommended that this option be enabled, as your processor(s)
>   may be damaged without it.
> 
> Now, I'm actually usally a big fan of not dragging around old gunk 
> forever, ABI be damned, but in this case this really won't do. 2.6.10 is 
> a recent maintenance release and I see for the new 3.0 branch:
> 
> http://www.lm-sensors.org/wiki/Download
> 
> ===
> Most third party monitoring applications do not yet work with the 
> library in this package. We are encouraging authors to port their 
> applications to the new library. We already have patches for xsensors 
> 0.60, gkrellm-2.3.0, net-snmp-5.4.1 (configure with 
> --with-mib-modules="ucd-snmp/lmsensorsMib" --with-ldflags="-lsensors"), 
> xfce4-sensors-plugin-0.10.99.2, kdebase-3.5.8(ksysguard), 
> sensors-applet-1.8.1 and ksensors-0.7.3-fedora-14.tar.gz (upstream is 
> dead this tarbal contains a version with all Debian's changes + 2 
> patches from Fedora, including lm_sensors-3.x support).
> ===
> 
> So it seems we have here a change to the kernel requiring a userspace 
> basically noone is ready for and which at least the (again, recent) 
> slackware 12.1 doesn't ship as a result. This is ABI breakage of the 
> really bad kind.
> 
> If there's not just something I'm missing, could someone please get 
> Linus a patch ASAP making whatever breaks lm_sensors 2 optional, 
> disabled by default and with a help text that warns that enabling it 
> requires a new lm_sensors userspace?
> 
> I haven't seen other complaints about this and would've expected them so 
> it might ofcourse be possible that I'm just missing something and have a 
> very specific problem; if in that case someone could advice what it 
> might be -- please do.
> 
> But if not, .26 is around the corner and requiring libsensors-3.0 must 
> really not be.
> 
> (*) 2.6.26-rc7 at least. I actually noticed this early in the -rc stage 
> but had too many other breakage at that point to worry about this one. I 
> just disabled the ACPI Thermal Zone support and forgot about it upto 
> this point.

Rene.
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