On Thu, 2008-05-01 at 10:04 +0200, Jean Delvare wrote:

On Mon, 28 Apr 2008 18:16:17 +0200, Kay Sievers wrote:

quoted

On Mon, 2008-04-28 at 17:40 +0200, Jean Delvare wrote:

quoted

Why would i2c device modaliases ever contain multiple strings? A devi=

ce

quoted

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can't have multiple names, can it?

=20
Like ACPI/PNP devices, which can have several compat id's, which means
that a single device can have "multiple names":
  $ cat /sys/bus/pnp/devices/00:09/id
  IBM0057
  PNP0f13

=20
Ah, I didn't know about this. Now I'm curious how it can work. Does it
mean that several drivers attempt to bind to this device?=20

=EF=BB=BFThey are usually all id's for the same type of device, and don't d=
escribe
multiple functions at the same time. In most cases the vendor id's, like
"IBM0057" here, do not match anything.

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Can't we just stop handle_moddevtable() from adding a tailing "*"
automatically, and just let the device types which need it, add it on
their own?

=20
For a lot subsystems it's fine to have it appended, as there is a
defined list of identifiers, which must appear in the same order, and
new identifiers are appended to the end. So the "*" still matches
modules with possibly extended modalias strings.

=20
I understand the logic, however I am skeptical how useful it is in
practice. If we add an identifier to the device aliases, then we also
update the corresponding modalias, so no in-tree driver can break. The
only case where it makes a difference, as far as I can see, is for
out-of-tree drivers. Am I correct?

=EF=BB=BFThat sounds correct, yes.

On top of that, I doubt that we
actually add new identifiers that frequently, do we?

Not that I know.

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We would also need to review all buses which export modalias, if they
need the "*" or not, and add them by hand, if needed.
=20
I guess, it's easier to introduce an additional parameter to
file2alias::do_table() and suppress the trailing "*" for i2c?

=20
That's one possibility, but I had a slightly different approach, which
is to just let the type-specific handlers add the trailing "*" by
themselves if they need it. This allows for optimization in a few
cases.
=20
Subject: modpost: i2c aliases need no trailing wildcard
=20
Not all device type aliases need a trailing wildcard, in particular
the i2c aliases don't. Don't add a wildcard by default in do_table(),
instead let each device type handler add it if needed.

...

The patch only changes the i2c aliases, all the rest is the same as
before (unless I messed up somewhere, that is.) Do you think this would
be acceptable for upstream? If you think it's better to add a parameter
to do_table() and let it add the "*" as it did so far, that's also fine
with me, I can update the patch to do that.

Looks fine to me.

If the content of:
  /lib/modules/$(uname -r)/modules.alias
looks correct after the patch, this should go in, I think.

Thanks,
Kay