Messages in this thread | | | Date | Tue, 14 Mar 2006 22:46:25 -0500 | From | "Mark M. Hoffman" <> | Subject | Re: sis96x compiled in by error: delay of one minute at boot |
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Hi Jean, Etienne:
<snip>
> On 2006-03-13, Etienne Lorrain wrote: > > Sorry, I was just assuming that while probing I2C hardware one per one, > > if one line is diplayed for each driver I do not have - then the kernel > > will at least display one line if it found something.
* Jean Delvare <khali@linux-fr.org> [2006-03-14 10:43:54 +0100]: > This is the way it should work, but unfortunately our i2c bus drivers > don't follow these rules. Almost all of them keep quiet when loaded > (except for i2c-sis96x, as you found out by yourself) but they also keep > quiet (unless debug is enabled) when a supported device is found, which > is not so good. > > Mark, can you provide a patch to your i2c-sis96x driver so that it'll > keep quiet when no supported device is found?
Lots of drivers printk messages when they load - IMO it's useful info. E.g. how else could Etienne discover that he accidentally built a kernel with dozens of i2c bus drivers (and probably all of the hwmon drivers) built-in by accident?
(But, I'll send the trivial patch to lm-sensors list if you still want it.)
<snip>
> > Removing the last PCA9564 gives me: > > Mar 13 21:46:48 ubuntu kernel: [ 47.699704] input: AT Translated Set 2 > > keyboard as /class/input/input1 > > Mar 13 21:46:48 ubuntu kernel: [ 47.702667] input: PC Speaker > > as /class/input/input2 > > Mar 13 21:46:48 ubuntu kernel: [ 47.705445] i2c /dev entries driver > > Mar 13 21:46:48 ubuntu kernel: [ 47.708637] i2c-parport: using default > > base 0x378 > > Mar 13 21:46:48 ubuntu kernel: [ 70.366096] hdaps: supported laptop not > > found! > > Mar 13 21:46:48 ubuntu kernel: [ 70.368750] hdaps: driver init failed > > (ret=-6)! > > You should also drop "Parallel port adapter (light)", it might cause > the same kind of delays and probably explains (part of) the 23 second > delay remaining.
<snip>
Wow, that's a huge delay. One alternative would be for i2c slaves to behave more like USB and do the probing asynchronous to driver load; i.e. 'modprobe w83627hf' returns before the chip is actually recognized and attached.
OTOH, that brings up all the related problems. E.g., you could no longer expect this simple fragment of a RC script to work...
modprobe i2c-sis96x modprobe asb100 sensors -s
Short of fixing all that... one has to accept that (1) i2c bus probing is slow, and (2) some i2c busses themselves are not reliably detectable...
...thus (3) it's a bad idea to build all of that into your monolithic kernel.
As Jean suggests, either use modules or build only the drivers for hardware you actually have.
Regards,
-- Mark M. Hoffman mhoffman@lightlink.com
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