[PATCH 1/1] ARM: OMAP2+: enable devtmpfs and devtmpfs automount

[PATCH 1/1] ARM: OMAP2+: enable devtmpfs and devtmpfs automount

[Javier Martinez Canillas]

Since udev-182, udev no longer creates device nodes under /dev
and this has to be managed by the kernel devtmpfs filesystem.

This means that a kernel built with the current OMAP2+ config
will not boot on a system with a recent udev.

Also, it is good to have /dev automatically mounted since some
non-initramfs based setups assumes this and don't manually mount it.

Signed-off-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk>
---
 arch/arm/configs/omap2plus_defconfig |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)

diff --git a/arch/arm/configs/omap2plus_defconfig b/arch/arm/configs/omap2plus_defconfig
index 6230304..6333e96 100644
--- a/arch/arm/configs/omap2plus_defconfig
+++ b/arch/arm/configs/omap2plus_defconfig
@@ -65,6 +65,8 @@ CONFIG_MAC80211_RC_PID=y
 CONFIG_MAC80211_RC_DEFAULT_PID=y
 CONFIG_UEVENT_HELPER_PATH="/sbin/hotplug"
 CONFIG_CONNECTOR=y
+CONFIG_DEVTMPFS=y
+CONFIG_DEVTMPFS_MOUNT=y
 CONFIG_MTD=y
 CONFIG_MTD_CMDLINE_PARTS=y
 CONFIG_MTD_CHAR=y
-- 
1.7.7.6

Re: [PATCH 1/1] ARM: OMAP2+: enable devtmpfs and devtmpfs automount

[Sekhar Nori]

On 11/21/2012 6:56 PM, Javier Martinez Canillas wrote:
> Since udev-182, udev no longer creates device nodes under /dev

Nit: Looks like this happened from udev-176 onward.

http://permalink.gmane.org/gmane.linux.hotplug.devel/17230

Whoever is taking the patch can _probably_ fix it up while applying.

> and this has to be managed by the kernel devtmpfs filesystem.
> 
> This means that a kernel built with the current OMAP2+ config
> will not boot on a system with a recent udev.

> Also, it is good to have /dev automatically mounted since some
> non-initramfs based setups assumes this and don't manually mount it.

For curiosity sake, any examples of such setups? I am using fedora 17 on
DaVinci and that doesn't seem to need it. Anyway, agreed that its better
to keep it enabled.

Thanks,
Sekhar

Re: [PATCH 1/1] ARM: OMAP2+: enable devtmpfs and devtmpfs automount

[Javier Martinez Canillas]

On 11/27/2012 09:34 AM, Sekhar Nori wrote:
> On 11/21/2012 6:56 PM, Javier Martinez Canillas wrote:
>> Since udev-182, udev no longer creates device nodes under /dev
> 
> Nit: Looks like this happened from udev-176 onward.
> 
> http://permalink.gmane.org/gmane.linux.hotplug.devel/17230
> 
> Whoever is taking the patch can _probably_ fix it up while applying.
> 

Hi Sekhar,

Thanks for clarifying this, I read that it was udev-182 from the Linux from
scratch documentation:
http://www.linuxfromscratch.org/lfs/view/jh/chapter07/udev.html

>> and this has to be managed by the kernel devtmpfs filesystem.
>> 
>> This means that a kernel built with the current OMAP2+ config
>> will not boot on a system with a recent udev.
> 
>> Also, it is good to have /dev automatically mounted since some
>> non-initramfs based setups assumes this and don't manually mount it.
> 
> For curiosity sake, any examples of such setups? I am using fedora 17 on
> DaVinci and that doesn't seem to need it. Anyway, agreed that its better
> to keep it enabled.
> 
> Thanks,
> Sekhar
> 

I'm using an IGEPv2 (TI OMAP3 DM3735) with an openembedded build and the oe udev
init script from the recipe I use seems to assume this.

Best regards,
Javier

Re: [PATCH 1/1] ARM: OMAP2+: enable devtmpfs and devtmpfs automount

[Tony Lindgren]

* Javier Martinez Canillas <javier.martinez@collabora.co.uk> [121121 05:29]:
> Since udev-182, udev no longer creates device nodes under /dev
> and this has to be managed by the kernel devtmpfs filesystem.
> 
> This means that a kernel built with the current OMAP2+ config
> will not boot on a system with a recent udev.
> 
> Also, it is good to have /dev automatically mounted since some
> non-initramfs based setups assumes this and don't manually mount it.

Thanks applying into omap-for-v3.8/fixes-for-merge-window.

Regards,

Tony
 
> Signed-off-by: Javier Martinez Canillas <javier.martinez@collabora.co.uk>
> ---
>  arch/arm/configs/omap2plus_defconfig |    2 ++
>  1 files changed, 2 insertions(+), 0 deletions(-)
> 
> diff --git a/arch/arm/configs/omap2plus_defconfig b/arch/arm/configs/omap2plus_defconfig
> index 6230304..6333e96 100644
> --- a/arch/arm/configs/omap2plus_defconfig
> +++ b/arch/arm/configs/omap2plus_defconfig
> @@ -65,6 +65,8 @@ CONFIG_MAC80211_RC_PID=y
>  CONFIG_MAC80211_RC_DEFAULT_PID=y
>  CONFIG_UEVENT_HELPER_PATH="/sbin/hotplug"
>  CONFIG_CONNECTOR=y
> +CONFIG_DEVTMPFS=y
> +CONFIG_DEVTMPFS_MOUNT=y
>  CONFIG_MTD=y
>  CONFIG_MTD_CMDLINE_PARTS=y
>  CONFIG_MTD_CHAR=y
> -- 
> 1.7.7.6
> 
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Re: [PATCH 1/1] ARM: OMAP2+: enable devtmpfs and devtmpfs automount

[Javier Martinez Canillas]

On Fri, Dec 14, 2012 at 7:10 PM, Tony Lindgren <tony@atomide.com> wrote:
> * Javier Martinez Canillas <javier.martinez@collabora.co.uk> [121121 05:29]:
>> Since udev-182, udev no longer creates device nodes under /dev
>> and this has to be managed by the kernel devtmpfs filesystem.
>>
>> This means that a kernel built with the current OMAP2+ config
>> will not boot on a system with a recent udev.
>>
>> Also, it is good to have /dev automatically mounted since some
>> non-initramfs based setups assumes this and don't manually mount it.
>
> Thanks applying into omap-for-v3.8/fixes-for-merge-window.
>
> Regards,
>
> Tony
>

Hi Tony,

I resend a v2 today: [PATCH v2 1/1] ARM: OMAP2+: omap2plus_defconfig:
enable devtmpfs and automount

That fixes an issue in the patch comments. Sekar Nori pointed out that
the first udev to make this a requirement was 176 not 182.
So probably is better if you can apply that one instead.

Thanks a lot and best regards,
Javier