On Wed, Mar 23, 2011 at 12:32 AM, Paul Mundt [off-list ref] wrote:

On Wed, Mar 23, 2011 at 12:22:05AM +0900, Magnus Damm wrote:

quoted

On Tue, Mar 22, 2011 at 11:33 PM, Paul Mundt [off-list ref] wrote:

quoted

On Tue, Mar 22, 2011 at 02:28:55PM +0000, Mark Brown wrote:

quoted

On Tue, Mar 22, 2011 at 11:26:19PM +0900, Magnus Damm wrote:

quoted

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?

I'm also curious as to why link order isn't a sufficient gaurantee like
it is for everyone else?

I believe all other i2c keyboard drivers use module_init().

We do not change initcall ordering around unless there is a reason to do
so, as it's assumed that a given initcall has been chosen for a reason.

Yes, obviously this driver is special and all other keypad drivers are wrong.

It would be interesting to hear why subsys_initcall() was put there in
the first place.

You have hit upon a bug or at least something timing related causing you
a delay and so have elected to push it down a level. That is of course
fine, but none of that is anywhere in your commit text leaving us to try
and figure out what exactly the point of this exercise is.

The keypad driver tries to use the I2C bus before the I2C bus driver
is initialized. Isn't that a pretty good reason to change the initcall
order?

Usually "because everyone else is doing it" and another driver is not,
there's a reason for that driver doing things differently. There are
certainly enough cases where initcall and link ordering is strongly
ordered for a reason that cosmetic/janitorial fixes are best rejected out
of hand.

So let's hear what other people have to say about this.

You had a reason, great. Next time put it in your commit text.

Whatever. Let me know which lines you'd like to add and I'll send a V2.

/ magnus