Re: [gentoo-dev] udev implementation

[Martin Schlemmer <azarah@gentoo.org>]

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On Tue, 2003-10-21 at 07:56, C. Brewer wrote:
>  I tried out the 0.2 version of udev today, and I realize that its way rough 
> so early in the development, but I must say I was disappointed with it's 
> current implementation ( and the lousy attitude of the udev FAQ "if you don't 
> like it stick with devfs" didn't help). Currently I have some small concerns 
> about adopting this as a whole ( somewhere on down the line)-
> 

Right.

> 1)The present package consists of a tarball with just about every device node 
> you could make (excepting small things like sound, ppp, more than 4 ttyS*'s)
> Is this going to be a standard, or will some form of intuitive /dev entries be 
> imp'd? IIRC, the tarball is about 1.4k device nodes, and I think I need 100 
> on the outside.
> 

Problem is that you need sysfs support, and currently only the scsi and
major block/char devices supports it (no input, sound, etc).

The tarball is only the initial stage, when better support is there (and
I have obviously learned a lot more :), it will be dropped.

> 2) Since this won't automatically create these nodes ( unless a hotplug event 
> occurs), or load the dependent modules, doesn't this seem like a step back to 
> the old system, but with a name-mapping steroided hotplug?
> 

Depends, creating specific entries in /sys/ will also cause these, and
when all drivers support sysfs ....

> 3) Don't get me wrong..I'm not flaming the package,and I realize devfs is crap 
> as well..but the score is devfsd( crap but makes nodes and loads mods on the 
> fly) and udev (maps names and supposedly does stuff with hotplugging that 
> hotplug never amounted to.( and is dev'd by the hotplug peeps?ironic)). All 

Eventually udev will do this as well (for me example, if with new udev,
and not having /sbin/udev in /proc/sys/kernel/hotplug, it auto loads
usb-storage + co, and creates /dev/sdc* [after deleting them of
course]).  You basically just have to think back initial devfs stage =)

> that aside, what is udev going to do for the desktop? I have devices I could 
> swap(USB) but with most comps coming with like 6 usb ports, I cant see more 
> than some pendrive swapping at user level. Yeah, I know theres peeps out 
> there with 80 pendrives and 8 hot-swappable hdd's, but is this the majority 
> of users? For the likely many of us who dont need to swap and have had the 
> same hardware on the same nodes that dont ever change..what does udev bring 
> to the table?
> 

When the driver register, it will still create /sys/ entries, and thus
the nodes you wish for (when it supports sysfs).

> Forgive me if I've gone delusional.. I was just under the impression that udev 
> was going to do everything that devfsd does now _and_ add name mapping, and 
> apparently I was wrong. I'm just planning for the future since seeing the 
> udev changes going into our init system.. we got no choice about the devfs 
> and I feel it's going the same way for udev. I'm not trying to slight the 
> obviously hard work that was put into it, but what about choice? to devfs or 
> not to devfs? to udev or not to udev? Or is it merely choice with package 
> selection, and not with the overall package that is Gentoo?
> 

If you want to do testing, and do not mind the slight issue, go udev -
if not, go devfs for now.


Thanks,

-- 

Martin Schlemmer
Gentoo Linux Developer, Desktop/System Team Developer
Cape Town, South Africa



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