Date: Tue, 27 Jan 2015 19:47:42 +0200 From: Konstantin Belousov <kostikbel@gmail.com> To: Andriy Gapon <avg@FreeBSD.org> Cc: svn-src-head@freebsd.org, svn-src-all@freebsd.org, src-committers@freebsd.org Subject: Re: svn commit: r277796 - in head/sys: dev/acpica dev/syscons dev/vt sys Message-ID: <20150127174742.GI42409@kib.kiev.ua> In-Reply-To: <201501271733.t0RHXJ3M058422@svn.freebsd.org> References: <201501271733.t0RHXJ3M058422@svn.freebsd.org>
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On Tue, Jan 27, 2015 at 05:33:19PM +0000, Andriy Gapon wrote: > Author: avg > Date: Tue Jan 27 17:33:18 2015 > New Revision: 277796 > URL: https://svnweb.freebsd.org/changeset/base/277796 > > Log: > hook userland threads suspend + resume into acpi suspend code > > Also, split power_suspend into power_suspend and power_suspend_early. > > power_suspend_early is called before the userland is frozen. > power_suspend is called after the userland is frozen. > > Currently only VT switching is hooked to power_suspend_early. > This is needed because switching away from X server requires its > cooperation, so obviously X server must not be frozen when that happens. > > Freezing userland during ACPI suspend is useful because not all drivers > correctly handle suspension concurrent with other activity. This is > especially applicable to drivers ported from other operating systems > that suspend all software activity between placing drivers and hardware > into suspended state. > In particular drm2/radeon (radeonkms) depends on the described > procedure. The driver does not have any internal synchronization > between suspension activities and processing of userland requests. > > Many thanks to kib for the code that allows to freeze and thaw all > userland threads. > > Note that ideally we also need to park / inhibit (non-special) kernel > threads as well to ensure that they do not call into drivers. > > MFC after: 17 days > > Modified: > head/sys/dev/acpica/acpi.c > head/sys/dev/syscons/syscons.c > head/sys/dev/vt/vt_core.c > head/sys/sys/eventhandler.h Thank you for fixing this. > > Modified: head/sys/dev/acpica/acpi.c > ============================================================================== > --- head/sys/dev/acpica/acpi.c Tue Jan 27 15:28:46 2015 (r277795) > +++ head/sys/dev/acpica/acpi.c Tue Jan 27 17:33:18 2015 (r277796) > @@ -2749,6 +2749,8 @@ acpi_EnterSleepState(struct acpi_softc * > return_ACPI_STATUS (AE_OK); > } > > + EVENTHANDLER_INVOKE(power_suspend_early); > + stop_all_proc(); It also makes sense to call syncer_suspend() after stop_all_proc(), I suppose. It would ensure that a failed resume still ends with the consistent filesystem metadata.
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