jk wrote: > Hans de Goede wrote at about 18:21:10 +0200 on Friday, April 6, 2007: > > jk wrote: > > >> jk wrote: > > >>> I have a p4pe board with the asb_100 sensor running under linux 2.6.20. > > >>> > > >>> I now notice that the sensors location varies between > > >>> /sys/bus/i2c/drivers/asb100/0-002d and /sys/bus/i2c/drivers/asb100/2-002d > > >>> between reboots. > > >>> > > >>> This creates problems for me since I use sensord and a crontab entry to read the > > >>> sensors but now the location of the sensors in /sys varies with each boot. > > >>> > > >>> Is this a bug? > > >>> If not is there a way to fix the location of the sensor directory in the /sys > > >>> heirarch? (Otherwise, I will need to write some klugey shell script to try to > > >>> find the location at boot-up and then automatically change the crontab entry > > >>> accordingly. > > >>> > > >>> Thanks! > > >>> > > > > > > Agreed. > > > > > > Note that I also seem to have an 'extra' layer in that my devices sit > > > in an asb100 subdirectory (see below) whereas yours seem to sit right > > > in the /sys/i2c/bus/devices directory. So I guess that mine already > > > has some 'naming' built in. > > > > > > > > > I guess my *practical* questions in the meantime until naming gets > > > changed are the following: > > > > > > 1. Why does the device number prefix change from '0' to '2' on > > > different boots? Also, why does the sensor jump to 2-002d when > > > there is NO 0-002d or 1-002d sensor? i.e. I would have thought you > > > would only get 2-002d if there were already a (conflicting) 0-002d > > > or 1-002d sensor. > > > > > > > The first number is the i2c bus, the second the address on the bus. > > Just to make sure I understand, it then seems that in my current > config, I have the following: > i2c bus #0 (p4pe motherboard): > asb100 (0-002d) > asb100 subclient (0-0048) > asb100 subclient (0-0049) > eeprom (0-0050) > eeprom (0-0051) > eeprom (0-0052) > i2c bus #1: (Winfast 2000XP Deluxe card) > tveeprom (1-0050) > tuner (1-0061) > i2c bus #1: (pcHDTV-5500??) > eeprom (2-0050) > > > > Note I believe I have only one asb100 sensor (corresponding to my > > > p4pe motherboard) but maybe the numbering gets mixed in with other > > > i2c devices (I have a nVIdia GeForce Ti 4600 graphic board, a > > > Winfast 2000XP Deluxe analog TV card, and a pcHDTV 5500 digital TV > > > card). > > > > > > 2. Why did none of this happen in the 2.4 kernels where I just used > > > as99127f-i2c-0-2d all the time? > > > > > > > Because modules where loaded there by initscripts / through /etc/modules.conf > > and that tended to happen in a fixed order. Now adays when udev registers > > itself as hotplug handler the kernel starts firing hotplug events for al > > already detected hardware and the drivers get loaded in parrallel, so there is > > no fixed order in the loading of the i2c bus masters, and thus no fixed > > addresses for the asb, as the address consists of busnumber-busaddress > > I am then surprised that many more people are not having this > problem. It would seem then that this "race condition" would apply to > anybody who had more than one i2c bus. > Perhaps though there are not many people who are using sensord/rrd > though... (however, if you are and set up the crontab as recommended > then you will get cron email errors mailed to you every 5 minutes :) > > > > 3. What if anything can I do to 'fix' the sensor to a specific prefix? > > > (Perhaps something analogous to what one does in modprobe.conf with > > > the index=n option or maybe something to force the boot order to be > > > consistent) > > > > > > > You could try to disable / blacklist non used i2c masters, but you have atleast > > the smbus controller on your board and one for your tvcard which you both need, > > another hack would be to modprobe the smbus driver from your rc.sysinit script > > before udev gets started. > > > > Regards, > > > > Hans > > I believe that I need all 3 i2c masters. > For the rc.sysinit hack, I assume you mean just insert a statement of > form: > modprobe asb100 > > Is that right? > About right, but you need to modprobe the driver for your smbus controller / the i2c master on your motherboard, as that is the one jumping from 0 - 2, the asb100 is always at 2d Regards, Hans
