On Mon, Jan 18, 2021 at 03:58:18PM +0100, Greg Kroah-Hartman wrote: > On Mon, Jan 18, 2021 at 04:48:53PM +0200, Andy Shevchenko wrote: > > On Mon, Jan 18, 2021 at 03:26:28PM +0100, Greg Kroah-Hartman wrote: > > > On Mon, Jan 18, 2021 at 04:12:38PM +0200, Mika Westerberg wrote: > > > > On Mon, Jan 18, 2021 at 02:50:33PM +0100, Rafael J. Wysocki wrote: > > > > > On Mon, Jan 18, 2021 at 8:27 AM Kai-Heng Feng > > > > > <kai.heng.feng@xxxxxxxxxxxxx> wrote: > > > > > > On Sat, Jan 9, 2021 at 12:25 AM Kai-Heng Feng > > > > > > <kai.heng.feng@xxxxxxxxxxxxx> wrote: > > > > > > > > > > > > > > Commit 8765c5ba19490 ("ACPI / scan: Rework modalias creation when > > > > > > > "compatible" is present") creates two modaliases for certain ACPI > > > > > > > devices. However userspace (systemd-udevd in this case) assumes uevent > > > > > > > file doesn't have duplicated keys, so two "MODALIAS=" breaks the > > > > > > > assumption. > > > > > > > > > > > > > > Based on the assumption, systemd-udevd internally uses hashmap to > > > > > > > store each line of uevent file, so the second modalias always replaces > > > > > > > the first modalias. > > > > > > > > > > > > > > My attempt [1] is to add a new key, "MODALIAS1" for the second > > > > > > > modalias. This brings up the question of whether each key in uevent > > > > > > > file is unique. If it's no unique, this may break may userspace. > > > > > > > > > > > > Does anyone know if there's any user of the second modalias? > > > > > > If there's no user of the second one, can we change it to OF_MODALIAS > > > > > > or COMPAT_MODALIAS? > > > > > > > > The only users I'm aware are udev and the busybox equivalent (udev, > > > > mdev) but I'm not sure if they use the second second modalias at all so > > > > OF_MODALIAS for the DT compatible string sounds like a good way to solve > > > > this. > > > > > > As udev seems to "break" with this (which is where we got the original > > > report from), I don't think you need to worry about that user :) > > > > > Does anyone use mdev anymore, and in any ACPI-supported systems? > > > > Yes, regularly. > > Ok, and how badly does it break when MODALIAS is multiple lines like > this? Or can it handle it? Since the mentioned change landed into v4.1 I never had a problem with my setup. From my point of view it doesn't affect anyhow mdev setup. -- With Best Regards, Andy Shevchenko