[Buildroot] [PATCH v1] package/busybox: Avoid "can't create /proc/sys/kernel/hotplug" error
Andy Shevchenko
andriy.shevchenko at linux.intel.com
Fri May 24 21:39:47 UTC 2019
On Fri, May 24, 2019 at 11:12:17PM +0200, Peter Korsgaard wrote:
> >>>>> "Andy" == Andy Shevchenko <andriy.shevchenko at linux.intel.com> writes:
>
> >> > But how can mdev work on such setups?
>
> > At least the script is used to initialize modules at the boot time.
> > What happens afterwards I didn't investigate. I have no such issues.
>
> You mean the:
>
> # coldplug modules
> find /sys/ -name modalias -print0 | xargs -0 sort -u | tr '\n' '\0' | \
> xargs -0 modprobe -abq
>
> That indeed does not depend on mdev working.
>
>
> >> To be clear, if mdev needs CONFIG_UEVENT_HELPER=y for hotplug
> >> notifications, then we should rather force that in linux/linux.mk and
> >> mention the dependency in the mdev help text rather than silently not
> >> having hotplug work.
> >>
> >> I have marked this patch as changes requested in patchwork.
>
> > Kernel can be built outside of Buildroot. Still this needs to be fixed.
>
> And just like all other packages that require specific kernel options
> enabled, if you are not using Buildroot to build the kernel then you
> have to ensure the kernel has the right config options enabled.
>
> I am not sure what you mean exactly with "Still this needs to be
> fixed". The only fix I can think of is what I mentioned above,
> E.G. document the need for CONFIG_UEVENT_HELPER in the help text and
> automatically enable it in linux.mk.
>
> Expecting mdev to work sensible on a system without uevent helper
> support isn't sensible, it is similar to having radvd (IPv6 router
> advertising daemon) work on a system without IPv6.
I'm not sure if mdev follows the change in the kernel, but uEvent helper is
obsolete mechanism.
--- 8< --- 8< --- 8< ---
The external binary /sbin/hotplug was used in earlier releases to inform Udev
about device state change. That has been replaced and Udev can now directly
listen to those events through Netlink.
--- 8< --- 8< --- 8< ---
--
With Best Regards,
Andy Shevchenko
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