LWN.net Logo

New column: Ask a kernel developer

New column: Ask a kernel developer

Posted Sep 24, 2009 23:38 UTC (Thu) by mjg59 (subscriber, #23239)
In reply to: New column: Ask a kernel developer by nix
Parent article: New column: Ask a kernel developer

It does. nvidia mobile hardware stubs out the c000:0003 entry point on first POST, because it pages in a pile of code from the system BIOS that doesn't fit in the legacy 64K window and so isn't there once the system is running.


(Log in to post comments)

New column: Ask a kernel developer

Posted Sep 25, 2009 6:27 UTC (Fri) by nix (subscriber, #2304) [Link]

Aha. So suspend-to-disk (e.g. tuxonice) works, but suspend-to-RAM won't,
then? I can't see how it could distinguish between POST-and-we're-booting
and POST-and-we're-resuming: the state of the hardware is identical.

New column: Ask a kernel developer

Posted Sep 25, 2009 6:28 UTC (Fri) by johill (subscriber, #25196) [Link]

There's no POST when resuming.

New column: Ask a kernel developer

Posted Sep 25, 2009 15:27 UTC (Fri) by nix (subscriber, #2304) [Link]

There surely is with tuxonice, which does a full ACPI S5 powerdown after hibernating. Suspend-to-RAM and lower suspend states are always iffier than full suspend-to-disk precisely because they don't turn the whole box off and let it reinitialize itself conventionally.

(I may have messed up terminology here: I can never remember which of 'suspend' and 'hibernate' is to disk and which to RAM. I've been talking about suspend-to-disk at all times, mainly because I've never managed to get suspending to RAM working with anything Linux-like *or* Windows-like. The last time I owned a machine *that* worked on was so long ago that it was running DOS...)

Suspend

Posted Sep 26, 2009 6:43 UTC (Sat) by job (guest, #670) [Link]

Here's another data point for you: I suspend-to-RAM my Thinkpad about four or five times a day and it works perfectly. Well, almost, the exception is the iwl3945 driver which crashes hard after a number of cycles (actually it's enough to 'ifconfig wlan0 down' and then 'up' a number of times) which means when the link state is wrong it's time to reboot (it's a distribution kernel and not mainline). Anyway, some hardware works better than others and that may be a good thing to keep in mind when shopping for hardware.

Suspend

Posted Sep 27, 2009 10:13 UTC (Sun) by nix (subscriber, #2304) [Link]

Yes, well, laptops are likelier to work with suspend-to-RAM than other
systems. I suspend several desktops to disk to save power: on not a single
one of them does suspend-to-RAM work, because it requires BIOS work that
the desktop vendors didn't do. Requiring things of BIOSes is always risky
(as we all know).

Suspend

Posted Sep 27, 2009 20:19 UTC (Sun) by khc (subscriber, #45209) [Link]

better yet, my desktop with 2.6.31 used to suspend to ram correctly, and after some distro updates (ubuntu 9.10) now it always fails. So it's is quite fragile even when it works.

Suspend

Posted Sep 27, 2009 13:15 UTC (Sun) by xoddam (subscriber, #2322) [Link]

I'm laughing! I have observed the same problem once or twice (also more irritatingly, a symptom similar to the old bug of not aging networks whilst suspended so my machine tries to hook up with the work network when I open it at home and vice versa).

I find rmmod works, though IIRC is not guaranteed to. So I happily rmmod iwlagn && insmod iwlagn and wireless lives indefinitely.

The only thing that crashes on me after extended use now is Firefox with its many tabs and sandboxed proprietary Flash player. Yet it all comes back in more-or-less the same state when I restart it, thanks to sqlite. Crash-only software rules, ok!

New column: Ask a kernel developer

Posted Sep 25, 2009 16:27 UTC (Fri) by mjg59 (subscriber, #23239) [Link]

Right, suspend to disk should work ok.

Copyright © 2013, Eklektix, Inc.
Comments and public postings are copyrighted by their creators.
Linux is a registered trademark of Linus Torvalds