Hi Ben, Joe and Mike, I am patching the kernel. Looking at the patch file you mentioned, I see one line difference. In debain 2.6.8 kernel, it uses schedule_timeout(HZ/100+1) instead of yield() stated in the patch. And I just tested the 2.6.8 kernel without patch, the modprobe fail problem appear immediately. Not the same I experienced in 2.6.14 kernel. Moreover, tested the 2.6.14 kernel with your patch appiled, modprobe fail problem also appears immediately. Running with "modprobe sc200_acx base=0x820,0", it return no delay and no error! Thanks a lot, Punky BGardner at Wabtec.com wrote: > Hi Mike, Joe - > > It looks like the scx200_acb driver scans two IO addresses by default > (0x820, 0x840). > One of them doesn't exist. That explains the ACBCTL2 readback problem. > =) > You should be able to get rid of that message by using the 'base' module > parameter. > Here's a guess at the format. > $ modprobe scx200_acb base=0x820,0 > > > In [1], Joe mentioned a 15 second delay. > > The scx200_acb driver has a flaw where it misses the NACK indication > when it tries to write to an address that doesn't exist. This causes it > to timeout instead of immediately returning a failure. Likely, your > hardware is 'scanning' for around 15 devices that don't exist. > > Refer to this patch for a possible fix: > http://lists.lm-sensors.org/pipermail/lm-sensors/2005-December/014716.ht > ml > > Another thing to do is to add 'ignore' parameters to modprobe so that > the chip drivers don't scan for devices that don't exist. > > For example, I use this for my lm83: > $ modprobe lm83 force=0,0x4c > ignore=0,0x18,0,0x19,0,0x1a,0,0x29,0,0x2a,0,0x2b,0,0x4d,0,0x4e > > Ben > > >>-----Original Message----- >>From: lm-sensors-bounces at lm-sensors.org >>[mailto:lm-sensors-bounces at lm-sensors.org] On Behalf Of >>Michael Renzmann >>Sent: Tuesday, January 03, 2006 1:53 AM >>To: lm-sensors >>Subject: scx200_acb: unexpected ACBCTL2 readback >> >>Hi. >> >>On the voyage-linux mailing list there recently has been a >>report about >>a problem related to scx200_acb in 2.6.x kernels. The >>original report is >>at [1], a short but more detailed analysis of the problem is at [2]. >> >>The problem seems to be that loading scx200_acb fails during >>the probing >>phase, but loading and using LM77 after that still works fine. Quoting >>[2]: >> >>=== cut === >>Same here with a non-voyage 2.6.11 kernel. I enabled >>debugging and added >>a bit more info into the relevant message and I get: >> >>i2c /dev entries driver >>scx200_acb: ACBCTL2 readback failed, got 0xff >> : probe failed >> >>The driver write 0x70 to ACBCTL2 and expects to read 0x70 back, but it >>gets 0xff instead. Looked into the manual briefly, but seems too >>complicated to figure out quickly. As you mention, lm77 works fine >>thereafter. Weird... >>=== cut === >> >>Comments? >> >>Bye, Mike >> >>[1] >>http://list.voyage.hk/pipermail/voyage-linux/2005-December/000548.html >>[2] >>http://list.voyage.hk/pipermail/voyage-linux/2006-January/000565.html >> >> >>_______________________________________________ >>lm-sensors mailing list >>lm-sensors at lm-sensors.org >>http://lists.lm-sensors.org/mailman/listinfo/lm-sensors >> >> > > > > _______________________________________________ > Voyage-linux mailing list > Voyage-linux at list.voyage.hk > http://list.voyage.hk/mailman/listinfo/voyage-linux
