Re: Migrating from static /dev to udev

["Brendan Moran" <bremoran@broadcom.com>]

Alan Jenkins wrote:
> On 9/28/09, Brendan Moran <bremoran@broadcom.com> wrote:
>   
>> Hi Alan,
>> I'm using virtually the same startup script as is used in Ubuntu
>> (attached).  It only uses $udevadm trigger, with no arguments.
>>     
>
> Well, I'm sure you can narrow it down.  You can always single-step the
> init script on a running system to see what's happening.
>   
It turns out it was pretty obvious:
> -n Starting kernel event manager...
> .
> -n Loading hardware drivers...
> [101] udev_monitor_enable_receiving: bind failed: No such file or 
> directory
> error initializing netlink socket
> [101] main: error initializing netlink socket
> udevadm[102]: bind failed: No such file or directory
>
> error: unable to subscribe to udev events
Checking the source, it appears that having 
udev_monitor_enable_receiving fail means that  
udev_monitor_new_from_netlink() is already failing.  I imagine that I'm 
missing a kernel config option, but I'm not sure what it is.


>> I didn't
>> expect that permissions would be an issue, as this system is running in
>> single user mode.
>>
>> Mounting /dev as a tmpfs makes perfect sense to me, however I'll have to
>> do some hacking before I can modify that.
>>     
>
> ?
>         if [ -z $DEVMOUNT ]; then
>             # initramfs didn't mount /dev, so we'll need to do that
>             mount -n -t tmpfs -o mode\a55 udev /dev
>         fi
>
> This will definitely cause some problems if you hadn't noticed it and
> left /lib/udev/devices empty.  Udev relies on /dev/null being present
> at startup.
>
> I think this is your main problem!  Perhaps it is somehow responsible
> for the later 'unknown: "uevent"' problem.  
I've fixed the empty device list problem, so the failed bind is the 
biggest problem now.

Thanks again,
Brendan
>>  I have a list of all the
>> devices to be created and placed in /dev already.  Currently, it's
>> expanded at compile time, but I should be able to change the target from
>> /dev to /lib/udev/devices.
>>
>> One additional thing that I need to do while migrating away from a
>> static /dev is to convert our current naming scheme for devices to one
>> which is consistent with the naming that udev uses by default.
>>
>> Thanks again,
>> Brendan
>>     
>
> Good luck
>
>   
>> Alan Jenkins wrote:
>>     
>>> Hi
>>>
>>> On 9/25/09, Brendan Moran <bremoran@broadcom.com> wrote:
>>>
>>>       
>>>> Hi,
>>>>         
>
> --
> A: Because it messes up the order in which people normally read text.
>   
>> Q: Why is top-posting such a bad thing?
>>     
>>> A: Top-posting.
>>>       
>>>> Q: What is the most annoying thing in e-mail?
>>>>         
>
>