[Buildroot] [PATCH 0/1] Bug in the boot process using mdev

[Luca Ceresoli <luca.ceresoli@comelit.it>]

Hi Thomas,

Thank you very much for your reply.

Thomas Petazzoni wrote:
...
> I initially implemented mdev support as you proposed, with a separate
> static device table for the few device nodes that are mandatory to get
> the system up to a point where mdev can be started.
>
> However, after discussions on the list, we decided that both our mdev
> and udev configurations should rely on devtmpfs. So when the mdev or
> udev mechanisms are selected in Buildroot configuration, we assume that
> devtmpfs will be mounted in /dev at boot time.
>
> This is automatically ensured when Buildroot is responsible for
> building the kernel. See linux/linux.mk :
>
> ifneq ($(BR2_ROOTFS_DEVICE_CREATION_STATIC),y)
>          $(call KCONFIG_ENABLE_OPT,CONFIG_DEVTMPFS,$(@D)/.config)
>          $(call KCONFIG_ENABLE_OPT,CONFIG_DEVTMPFS_MOUNT,$(@D)/.config)
> endif
>
> However, if you build your kernel separately, then indeed, it's your
> responsibility to make sure that DEVTMPFS and DEVTMPFS_MOUNT are
> enabled.

Shame on me!
My kernel _is_ built by buildroot, and the two DEVTMPFS options _are_
activated. The problem is that I was unaware of that, and went on using
the previously compiled kernel uImage I had lying in /dev/tftp.

>
> This is probably a requirement that should be better documented, at
> least in the static/devtmpfs/mdev/udev configuration option help.
>

Really, as I just proved in such a clumsy way.
But I admit I'd rather wait for it to be done by anybody seriously
knowing the issue (which is probably you). :)

Luca

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Luca Ceresoli
Comelit R&D - Progettazione Software

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Prima di stampare pensa all'ambiente / Think about environment before printing
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