Re: RTC device Major/Minor Number

[Paul M. <le...@li...>]

On Wed, Aug 29, 2007 at 04:36:37PM +0200, EXTERNAL Brunner Markus (Praktikant;  ST-FIR/Eng) wrote:
> why isn't /dev/rtc the well known "c 10 135" device that it's on x86,
> but a magic undocumented "c 254 0" device? 
> Devices.txt lists this major number as LOCAL/EXPERIMENTAL USE. 
> 
This is a bit of an intentional namespace conflict. The 10 135 device is
a legacy driver, and even x86 is moving away from that in favour of
dynamic numbers. The new drivers/rtc/ subsystem is entirely dynamic, so
all of the architectures using this behave the same way. Static device
nodes are a relic of the past, and new system designs should not depend
on them.

Even without udev, you can still get a link to the device node via sysfs,
so it's possible to script around this, but you really should be using
udev. hwclock and friends generally work transparently regardless of
whether the legacy driver is in use or not.