Gentoo Archives: gentoo-dev

From: Luke-Jr <luke-jr@×××××××.org>
To: gentoo-dev@l.g.o, Stuart Stegall <stuart@×××××××××××××.com>
Subject: Re: [gentoo-dev] Re: [gentoo-desktop] X freezing?
Date: Thu, 28 Oct 2004 17:55:24
Message-Id: 200410281755.37740.luke-jr@utopios.org
In Reply to: Re: [gentoo-dev] Re: [gentoo-desktop] X freezing? by Greg KH
1 On Thursday 28 October 2004 5:24 pm, Greg KH wrote:
2 > On Thu, Oct 28, 2004 at 04:16:14PM +0000, Luke-Jr wrote:
3 > > > On Thu, Oct 28, 2004 at 02:05:37AM +0000, Luke-Jr wrote:
4 > > > > On Thursday 28 October 2004 1:53 am, you wrote:
5 > > > > sysfs works great. I use it regardless of udev. The main problem is
6 > > > > that udev defeats the entire purpose of modules. Using udev, you must
7 > > > > preload any modules you want to use manually. If you do that, you
8 > > > > might as well compile them into your kernel. I'd much rather not have
9 > > > > the driver for any of my devices loaded until I actually need them.
10 > > >
11 > > > See the udev FAQ for the answers to this question. In short, no, udev
12 > > > does NOT "defeat the entire purpose of modules." Geesh, where do
13 > > > people get ideas like this from...
14 > > >
15 > > >From udev FAQ:
16 > > >Q: But udev will not automatically load a driver if a /dev node is
17 > > > opened when it is not present like devfs will do.
18 > > >A: If you really require this functionality, then use devfs. It is
19 > > > still present in the kernel."
20 > >
21 > > In short, the "solution" to that problem according to the udev FAQ is to
22 > > not use udev.
23 >
24 > If you want to rely on such a broken, antiquated system, sure, don't use
25 > udev.
26
27 At least it does what is neccesary, even if it is broken. If udev lacks the
28 neccesarily functionality, it doesn't matter that it works.
29
30 >
31 > > >Q: Oh come on, pretty please. It can't be that hard to do.
32 > > >A: Such a functionality isn't needed on a properly configured system.
33 > > > All devices present on the system should generate hotplug events,
34 > > > loading the appropriate driver, and udev will notice and create the
35 > > > appropriate device node. If you don't want to keep all drivers for
36 > > > your hardware in memory, then use something else to manage your modules
37 > > > (scripts, modules.conf, etc.) This is not a task for udev.
38 > >
39 > > What makes you think I want the drivers loaded just because the device is
40 > > connected/available? It may be insignificantly small, but I don't see a
41 > > reason to use the RAM neccesary nor decrease the stability of my systems
42 > > for something I'm not using.
43 > > For example, my motherboard has a parallel port, but I don't want the
44 > > driver loaded unless I'm actually using it (which is fairly rare).
45 >
46 > Great, then have a "load lp module" script that you run to load the
47 > driver.
48
49 Nor do I wish to be aware of software using it.
50
51 > Don't rely on accessing the device node to load a module for you.
52
53 Why not? Makes perfect sense.
54
55 > It's just wrong, and is not the way the Linux kernel has been evolving over
56 > the past 4 years.
57
58 How do you figure this? Linux has done automatic module loading for quite a
59 while, even before devfs. Even if udev simply created the device nodes for
60 unloaded modules, it would still work.
61
62 > > > > > But they would still be using sysfs. Also I am curious as to what
63 > > > > > "new" USB Mass Storage driver you are referring to? The current
64 > > > > > mainstream kernel's driver was updated about 4 months ago, and
65 > > > > > still presents itself as a low level scsi driver to the kernel
66 > > > > > (meaning it needs scsi.ko and sd.ko)
67 > > > >
68 > > > > Well, I noticed they were suddenly "udX" when I moved to 2.6.9...
69 > > >
70 > > > "ubX", not "udX". And that happened because you selected the block UB
71 > > > driver. So you asked the kernel to do this, nothing "sudden" about it
72 > > > at all.
73 > > >
74 > > >From kernel configuration:
75 > > >Low Performance USB Block driver (BLK_DEV_UB)
76 > > >
77 > > >This driver supports certain USB attached storage devices
78 > > >such as flash keys.
79 > >
80 > > It was newly available and the description implies that it is a desirable
81 > > option.
82 >
83 > "Low Performance" is a desirable option? "flash keys" for your
84 > IDE/SCSI/USB bridge device?
85
86 I also use Flash keys. I had no intention of using this module for the bridge,
87 but for those.
88 --
89 Luke-Jr
90 Developer, Utopios
91 http://utopios.org/
92
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