[Buildroot] Problems with udev buildroot

[Buildroot] Problems with udev buildroot

[Heiko Helmle]

Hello List,

I'm a bit new and I'm trying to build a small x86 buildroot with udev.

So far I just enabled building a pretty default .config (just enabled a kernel with i386 defconfig and set udev for /dev management).

Unfortunately on 2011.8rc1 and the latest git this doesn't work right:

---
unable to access '/sys//devices/platform/i8042/serio1/input/input2
/sbin/modprobe: invalid option -- b
--
then comes the busybox help for modprobe 
--
unable to access 'sys//devices/platform/i8042/serio1/input/input2/mouse0
unable to access 'sys//devices/platform/i8042/serio1/input/input2/event2
can't open /dev/tty1: No such file or directory
can't open /dev/tty1: No such file or directory

[Buildroot] Problems with udev buildroot

[Heiko Helmle]

Hello

Hit the send button too early :)

it seems like /dev/null is missing and the generated image isn't able to mount anything...

> ----- Urspr?ngliche Nachricht -----
> Von: Heiko Helmle
> Gesendet: 08.08.11 21:15 Uhr
> An: buildroot at busybox.net
> Betreff: [Buildroot] Problems with udev buildroot
> 
> Hello List,
> 
> I'm a bit new and I'm trying to build a small x86 buildroot with udev.
> 
> So far I just enabled building a pretty default .config (just enabled a kernel with i386 defconfig and set udev for /dev management).
> 
> Unfortunately on 2011.8rc1 and the latest git this doesn't work right:
> 
> ---
> unable to access '/sys//devices/platform/i8042/serio1/input/input2
> /sbin/modprobe: invalid option -- b
> --
> then comes the busybox help for modprobe 
> --
> unable to access 'sys//devices/platform/i8042/serio1/input/input2/mouse0
> unable to access 'sys//devices/platform/i8042/serio1/input/input2/event2
> can't open /dev/tty1: No such file or directory
> can't open /dev/tty1: No such file or directory
> _______________________________________________
> buildroot mailing list
> buildroot at busybox.net
> http://lists.busybox.net/mailman/listinfo/buildroot

[Buildroot] Problems with udev buildroot

[Peter Korsgaard]

>>>>> "Heiko" == Heiko Helmle <helman@gmx.net> writes:

 Heiko> Hello
 Heiko> Hit the send button too early :)

 Heiko> it seems like /dev/null is missing and the generated image isn't able to mount anything...

Do you have CONFIG_DEVTMPFS_MOUNT enabled in the kernel? If so, that
should take care of /dev/null.

-- 
Bye, Peter Korsgaard

[Buildroot] Problems with udev buildroot

[Heiko Helmle]

-- snip --
[hel at verflixtsl6 xtest]$ grep DEVTMPFS build/linux-2.6.39.4/.config 
CONFIG_DEVTMPFS=y
CONFIG_DEVTMPFS_MOUNT=y
-- snip --

I'm using i386 defconfig without any changes (yet) - this seems to enable DEVTMPFS by default.

But after a rebuild with the same .config it looks different now - I'll do a clean rebuild and check again.

> ----- Urspr?ngliche Nachricht -----
> Von: Peter Korsgaard
> Gesendet: 08.08.11 21:43 Uhr
> An: Heiko Helmle
> Betreff: Re: Problems with udev buildroot
> 
> >>>>> "Heiko" == Heiko Helmle <helman@gmx.net> writes:
> 
> ?Heiko> Hello
> ?Heiko> Hit the send button too early :)
> 
> ?Heiko> it seems like /dev/null is missing and the generated image isn't able to mount anything...
> 
> Do you have CONFIG_DEVTMPFS_MOUNT enabled in the kernel? If so, that
> should take care of /dev/null.
> 
> -- 
> Bye, Peter Korsgaard

[Buildroot] Problems with udev buildroot

[Heiko Helmle]

aah sorry - the rookie found his mistake:

I'm using a cpio'd filesystem as initramfs - and that disables devtmpfs_mount - according to kernel doc, initramfs has to to mount devtmpfs manually to use it.

So I'm still not quite sure if it'd be better to edit the inittab to mount devtmpfs or just put the basic nodes statically into /dev...

Am 08.08.2011 um 22:07 schrieb Heiko Helmle:

> -- snip --
> [hel at verflixtsl6 xtest]$ grep DEVTMPFS build/linux-2.6.39.4/.config 
> CONFIG_DEVTMPFS=y
> CONFIG_DEVTMPFS_MOUNT=y
> -- snip --
> 
> I'm using i386 defconfig without any changes (yet) - this seems to enable DEVTMPFS by default.
> 
> But after a rebuild with the same .config it looks different now - I'll do a clean rebuild and check again.
> 
>> ----- Urspr?ngliche Nachricht -----
>> Von: Peter Korsgaard
>> Gesendet: 08.08.11 21:43 Uhr
>> An: Heiko Helmle
>> Betreff: Re: Problems with udev buildroot
>> 
>>>>>>> "Heiko" == Heiko Helmle <helman@gmx.net> writes:
>> 
>>  Heiko> Hello
>>  Heiko> Hit the send button too early :)
>> 
>>  Heiko> it seems like /dev/null is missing and the generated image isn't able to mount anything...
>> 
>> Do you have CONFIG_DEVTMPFS_MOUNT enabled in the kernel? If so, that
>> should take care of /dev/null.
>> 
>> -- 
>> Bye, Peter Korsgaard
> 
> _______________________________________________
> buildroot mailing list
> buildroot at busybox.net
> http://lists.busybox.net/mailman/listinfo/buildroot

[Buildroot] Problems with udev buildroot

[Peter Korsgaard]

>>>>> "Heiko" == Heiko Helmle <helman@gmx.net> writes:

 Heiko> aah sorry - the rookie found his mistake:

 Heiko> I'm using a cpio'd filesystem as initramfs - and that disables
 Heiko> devtmpfs_mount - according to kernel doc, initramfs has to to
 Heiko> mount devtmpfs manually to use it.

 Heiko> So I'm still not quite sure if it'd be better to edit the
 Heiko> inittab to mount devtmpfs or just put the basic nodes statically
 Heiko> into /dev...

We have native initramfs support in BR, which contains a workaround for
the kernel not mounting devtmpfs - Why are you not using that?

-- 
Bye, Peter Korsgaard

[Buildroot] Problems with udev buildroot

[Heiko Helmle]

Am 09.08.2011 um 08:31 schrieb Peter Korsgaard:
> 
> 
> We have native initramfs support in BR, which contains a workaround for
> the kernel not mounting devtmpfs - Why are you not using that?

I guess you mean the one that gets embedded in the kernel image automatically? I wasn't aware that in that case the filesystem receives a workaround. I'll try that next - thank you!

Best Regards
	Heiko