On Wednesday, February 20, 2008 10:37 am Linus Torvalds wrote: > This *sounds* like some part of the suspend-to-disk sequence is doing > something stupid like trying to access the screen after it has been turned > off, which doesn't surprise me at all. My oft-stated opinion has been that > suspend-to-disk isn't a suspend at all, and should never have been > confused with "suspending" anything. > > It's "snapshot-and-restore", and my opinion is that: > > - it should *never* call "suspend()"/"resume()" at all (that should be > reserved purely for suspend-to-RAM and has real power management > issues!) > > - it should have a totally separate "halt/unhalt/restore" thing > that has nothing what-so-ever to do with power management, and is > purely about stopping the hardware for things like USB and network > cards (which otherwise do things like scan their command lists > asynchronously) and making sure that the driver state is consistent > with that stopped hw state. > > - the people who confuse snapshot/restore with suspend/resume are > horrible people that cause problems exactly because driver people then > get those things mixed up, and something like the video suspend/resume > should probably never have impacted suspend-to-disk in the first place! Totally agreed. I remember when I started getting hibernation bug reports against this new code and boggling at how hibernate was actually done. The driver actually gets its ->suspend routine called twice with two different pm_message_t values. We tried to do different stuff depending on the pm_message_t (like only putting the device in D3hot if PM_EVENT_SUSPEND), but it appears we're not doing enough... > So there seems to be two (probably largely independent) problems: > > - the hang at shutdown that requires you to press-and-hold the power > button to actually cut power. > > At a guess: putting the VGA device into D3hot makes the ACPI code that > actually does the shutoff unhappy. Probably because it wants to access > the device, and ends up not ever getting the replies it wants, since > the hardware has been turned off. Sounds like a good theory... now if we could just use set_power_state in the suspend case only. That's what the latest code *tries* to do... JEsse - To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
