On Tue, 31 Jan 2012 02:44:29 +0600 Roman Mamedov wrote: > On Sat, 7 Jan 2012 16:45:02 -0800 > Guenter Roeck wrote: > > > > - Michael Ott reported with Debian kernel 2.6.38-3 (which is closely > > > based on stable v2.6.38.2): > > > > > > syslog tell me every few seconds: > > > i2c i2c-0: mv64xxx: I2C bus locked, block: 1, time_left: 0 > > > > > > - Manuel Roeder reported the same and found that upstream v2.6.38 > > > triggers the problem and v2.6.37.6 does not. > > > > > > - Roman Mamedov finds the bug present in Debian 3.1.6-1 (which > > > is closely based on stable v3.1.6) and Debian 2.6.37-2 (based on > > > stable v2.6.37.2) but not Debian 2.6.37-1 (based on mainline > > > v2.6.37). > > > > > > The regression range described above seems a little inconsistent to > > > me, so maybe there's something more going on. > > > > > Points to commit eda6bee6c7e67b5bd17bdbced0926f5687f686d5 (i2c-mv64xxx: send repeated START > > between messages in xfer). Maybe you can back it out and see if it makes a difference. > > Hello, > > I have just confirmed that the problem still occurs in the current > 3.2.2, and is indeed solved by rolling-back the referred commit. > > Should be noted that beside the "I2C bus locked" messages in dmesg, the described problem > manifested itself in the inability to read the temperature sensor value or adjust the fan > speed on the D-Link DNS-323. On all problematic kernels the built-in fan of DNS-323 does not > rotate and this risks overheating the device and disks installed in it. Also if anyone decides to further debug this, I should note that once a 'problematic' kernel has booted once on the device, a full power-off seems to be required, before a 'good' kernel can work properly. Without this, even a working kernel will manifest the same problem, it looks like something in the hardware gets locked-up hard and stays that way even across reboots. If someone's unaware of this, it can completely foil any attempt at git bisecting. -- With respect, Roman ~~~~~~~~~~~~~~~~~~~~~~~~~~~ "Stallman had a printer, with code he could not see. So he began to tinker, and set the software free."