On Tue, Mar 22, 2011 at 11:28 PM, Mark Brown <broonie@xxxxxxxxxxxxxxxxxxxxxxxxxxx> wrote: > On Tue, Mar 22, 2011 at 11:26:19PM +0900, Magnus Damm wrote: > >> The tca6416 driver makes use of the I2C bus for chatting >> with the actual hardware device. Without this patch both >> the I2C bus driver and the tca6416 driver are initialized >> at the subsys_initcall() level. This may lead to problems >> with the tca6416 driver being initialized before the I2C >> bus driver. > > While this change seems reasonable I'm curious what the problems caused > by out of order registration are? The boot up time is delayed with 5 seconds or so due to a delay that only happens if subsys_initcall() level is used for both tca6416 and the I2C driver. By disabling the tca6416 driver in the kernel configuration the delay goes away. I have not tracked it down further than using module_init() instead of subsys_initcall() in the tca6416 driver. This because tca6416-keypad.c is the only keyboard driver that uses subsys_initcall(). If I enable initcall_debug then I get this output: calling input_init+0x0/0x114 @ 1 initcall input_init+0x0/0x114 returned 0 after 0 usecs calling tca6416_keypad_init+0x0/0x10 @ 1 initcall tca6416_keypad_init+0x0/0x10 returned 0 after 0 usecs calling sh_mobile_i2c_adap_init+0x0/0xc @ 1 i2c-sh_mobile i2c-sh_mobile.0: clocks managed by runtime pm input: tca6408-keys as /devices/platform/i2c-sh_mobile.0/i2c-0/0-0020/input/input0 [delay] If my interpretation of the log above is correct then tca6416_keypad_init() is executed before sh_mobile_i2c_adap_init(). As for link order, i2c is located after input in driver/Makefile. I believe that matches well with the log above. Thanks, / magnus -- To unsubscribe from this list: send the line "unsubscribe linux-i2c" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
