On Tue, 10 Jun 2008 09:27:34 +1200, Ryan Mallon wrote: > David Brownell wrote: > > On Monday 09 June 2008, Ryan Mallon wrote: > > > >>> Talk to i2c and framebuffer people about changing the link order. > >>> > >>> i2c should really be initialised before framebuffer devices because > >>> framebuffer devices tend to want to read DDC from monitors, which is > >>> basically a I2C EEPROM in the monitor.
This is already the case. i2c-core is initialized with subsys_initcall(), so it's available to all drivers initialized with module_init(). > >>> ... but there's probably some reason why it's done the way it is today, > >>> and changing it could well cause stuff to break. > >>> > >> We have made i2c the first driver subsystem to come up in our 2.6.20 > >> kernel since we use i2c io expanders for power domain control. All we > >> did was change drivers/Makefile so that obj-$(CONFIG_I2C) += i2c/ is at > >> the very top of the file. We didn't have any problems with doing this. > >> YMMV of course. Why don't you simply initialize the drivers in question with subsys_initcall()? That's what i2c-pnx, i2c-omap, i2c-davinci and tps65010 are doing at the moment. > > OMAP does much the same thing, for the same reason, and the I2C > > adapter gets initialized earlier too (so power management chips > > will be fully usable before driver_initcall code runs). > > > > Unless there's a downside on x86, I'd just suggest someone submit > > a patch moving I2C init "early" so it merges in 2.6.27 ... cc to > > LKML to scare out more potential problems, but I have a hard time > > imagining there'd really be any. > > Okay, heres the patch. Is untested though (other than our experience > under 2.6.20), so it probably needs some people to test. I'm not > subscribed to LKML, so can people CC me if necessary. > > Signed-off-by: Ryan Mallon <[EMAIL PROTECTED]> > > diff --git a/drivers/Makefile b/drivers/Makefile > index f65deda..9eaf236 100644 > --- a/drivers/Makefile > +++ b/drivers/Makefile > @@ -5,6 +5,7 @@ > # Rewritten to use lists instead of if-statements. > # > > +obj-y += i2c/ > obj-$(CONFIG_HAVE_GPIO_LIB) += gpio/ Some i2c bus drivers bit-bang GPIO pins... > obj-$(CONFIG_PCI) += pci/ ... and many are PCI devices, so will this work OK? > obj-$(CONFIG_PARISC) += parisc/ > @@ -61,7 +62,6 @@ obj-$(CONFIG_GAMEPORT) += input/gameport/ > obj-$(CONFIG_INPUT) += input/ > obj-$(CONFIG_I2O) += message/ > obj-$(CONFIG_RTC_LIB) += rtc/ > -obj-y += i2c/ > obj-$(CONFIG_W1) += w1/ > obj-$(CONFIG_POWER_SUPPLY) += power/ > obj-$(CONFIG_HWMON) += hwmon/ -- Jean Delvare _______________________________________________ i2c mailing list [email protected] http://lists.lm-sensors.org/mailman/listinfo/i2c
