Gentoo Archives: gentoo-user

From: Dale <rdalek1967@×××××.com>
To: gentoo-user@l.g.o
Subject: Re: [gentoo-user] /dev/rtc => rtc0
Date: Sat, 31 Jan 2009 23:18:18
Message-Id: 4984DC00.5020707@gmail.com
In Reply to: Re: [gentoo-user] /dev/rtc => rtc0 by Mark Knecht
1 Mark Knecht wrote:
2 > On Sat, Jan 31, 2009 at 2:43 PM, Dale <rdalek1967@×××××.com> wrote:
3 >
4 >> Mark Knecht wrote:
5 >>
6 >>> Hi,
7 >>> I know nothing of this part of the Linux boot process. If it's
8 >>> *fairly* simple can someone point me at the right stuff to understand
9 >>> how Gentoo creates a link from /dev/rtc to rtc0? When in the boot
10 >>> process does this link become valid?
11 >>>
12 >>> Is it something that's held in a file and recreated from that file
13 >>> on each boot? Is it created automagically by Gentoo Angels that look
14 >>> after my well being but seldom reveal themselves? Is it created by the
15 >>> kernel itself when something is specifically configured to do so?
16 >>> Something else?
17 >>>
18 >>> Thanks,
19 >>> Mark
20 >>>
21 >>> lightning src # uname -a
22 >>> Linux lightning 2.6.27-gentoo-r8 #6 Fri Jan 30 18:55:56 PST 2009
23 >>> x86_64 AMD Athlon(tm) 64 Processor 3000+ AuthenticAMD GNU/Linux
24 >>> lightning src # ls -al /dev/rtc*
25 >>> lrwxrwxrwx 1 root root 4 2009-01-30 10:58 /dev/rtc -> rtc0
26 >>> crw-r--r-- 1 root root 254, 0 2009-01-30 10:58 /dev/rtc0
27 >>> lightning src #
28 >>>
29 >>>
30 >>>
31 >>>
32 >> From my understanding udev creates all the "stuff" in /dev. You can
33 >> change the rules that it uses to make them tho. I think there is
34 >> documentation on gentoo.org to help with that. So far, mine has worked
35 >> well enough. Lucky I guess.
36 >>
37 >> That help?
38 >>
39 >> Dale
40 >>
41 >
42 > Hi Dale,
43 > While poking around in a bunch of different kernel config files -
44 > some gentoo-sources - some not - I found there is an option in
45 >
46 > Device Drivers -> RTC
47 >
48 > that ONLY shows up when you tell the kernel to build the support in.
49 > (I.e. - not off or modular) The option says
50 >
51 > <*> Set system time from RTC on startup or resume
52 > (rtc0) RTC used to set the system time
53 >
54 > So, it appears it's a kernel oriented thing which allows it to get set
55 > very early in the boot process. My problem on a kernel I built
56 > yesterday was "File has a date in the future" sort of messages. I had
57 > this set as modular so it couldn't load that early. The other problem
58 > was that since it was a module and apparently I didn't load that
59 > module the command hwclock -r failed.
60 >
61 > I've reconfigured the kernel and will build it and test after I get
62 > finished with an emerge -e world later today.
63 >
64 > Thanks for the response. Hope this info helps someone else in the
65 > future. (and me after the reboot!) ;-)
66 >
67 > Cheers,
68 > Mark
69 >
70 >
71 >
72
73 My CMOS time chip sucks on this mobo. Everything else rocks but that
74 stupid clock and yes I have checked the battery. Anyway, I get that
75 error all the time. If I just reboot it does all right but if I do a
76 shutdown, that error pops up. Sometimes it may only be a few seconds
77 off, sometimes several hours to a day. I have never had it hurt
78 anything here tho. It just warns you I guess.
79
80 Dale
81
82 :-) :-)