On Wed, 2014-07-30 at 22:50 +0200, Goffredo Baroncelli wrote: > Hi All, > > I am writing to you Jean and Benjamin because it seem that both > worked on these items. > > On a PowerMac G4 I noticed that between the kernel v3.2 and v3.14 I lost > the fan management. > > I found on internet other references to this kind of problem [2]
Patches look good, thanks. Jean do you want to apply them or should I ? Cheers, Ben. > > **How reproduce: > - booting with the kernel 3.2, the fan is "quite" silent. > The module therm_windtunnel is loaded and in the log there are > lines like: > > [ 1342.614956] CPU-temp: 58.7 C, Case: 33.7 C, Fan: 5 (tuned +0) > [ 1390.637793] CPU-temp: 58.6 C, Case: 33.6 C, Fan: 5 > > I had also access to the temperature via the sysfs files: > /sys/devices/temperature/case_temperature > /sys/devices/temperature/cpu_temperature > > > - booting with the kernel 3.14, the fan is very loud. The module > therm_windtunnel is not loaded. In the log there aren't any message > related to the temperature. The sysfs entries don't exist. > > > ** Analysis > In these Apple machines the module i2c-powermac requires the > i2c drivers provided by the module therm_windtunnel. > > Between the kernel v3.2 and v3.14 [1] some patches changed the > driver name requested by the i2c-powermac module, > so the therm_windtunnel modules is not instantiated anymore. > > > ** Proposed solution > In the following emails I sent you three patches to solve this > problem (tested on my PowerMac G4) > > 1) change the driver name > therm_ds1775 -> MAC,ds1775 > therm_adm1030 -> MAC,adm1030 > so the i2c driver are instantiated by i2c-powermac > > 2) remove the (unused) method do_attach from the i2c-driver > 3) add two parameters to the therm_windtunnel module > to control the kernel log message > > The patch 1) solve the problem. The patch 2) is a small cleanup. > The patch 3) allow a better control of the log in dmesg. > > Could you be so kindly to apply these patches ? > > BR > G.Baroncelli > > > > [1] I think that the guilty commit is > > commit 81e5d8646ff6bf323dddcf172aa3cef84468fa12 > Author: Benjamin Herrenschmidt <b...@kernel.crashing.org> > Date: Wed Apr 18 22:16:42 2012 +0000 > > i2c/powermac: Register i2c devices from device-tree > > This causes i2c-powermac to register i2c devices exposed in the > device-tree, enabling new-style probing of devices. > > Note that we prefix the IDs with "MAC," in order to prevent the > generic drivers from matching. This is done on purpose as we only > want drivers specifically tested/designed to operate on powermacs > to match. > > This removes the special case we had for the AMS driver, and updates > the driver's match table instead. > > Signed-off-by: Benjamin Herrenschmidt <b...@kernel.crashing.org> > > [2] There is the debian bug #741663 which highlight the same problem. In > the bug discussion there is a patch like the my ones. > > See also > https://lists.ozlabs.org/pipermail/linuxppc-dev/2012-July/099561.html > > > > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/