Date: Sat, 26 Sep 2015 00:26:31 -0700 From: Colin Percival <cperciva@freebsd.org> To: Jung-uk Kim <jkim@FreeBSD.org>, John Baldwin <jhb@freebsd.org>, "freebsd-acpi@freebsd.org" <freebsd-acpi@freebsd.org>, Dan Lukes <dan@obluda.cz>, ian Smith <smithi@nimnet.asn.au> Subject: Re: disabling sleep when shutting down Message-ID: <560648A7.4030708@freebsd.org> In-Reply-To: <5602DE8D.3020102@FreeBSD.org> References: <55FA3848.7090802@freebsd.org> <55FB233D.2080000@FreeBSD.org> <55FB48E3.20401@freebsd.org> <55FC4F13.3090603@FreeBSD.org> <55FC57F9.3050702@yahoo.com> <55FE5D54.1030806@freebsd.org> <5601A863.5070406@FreeBSD.org> <560262BF.7090107@freebsd.org> <5602DE8D.3020102@FreeBSD.org>
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This is a multi-part message in MIME format. --------------050603020603000908060907 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Hi all, I think there is consensus for: * Using a sysctl (simpler than a device node), * Setting this sysctl on all architectures, * Calling the sysctl kern.suspend_blocked, * Consulting the sysctl from the ACPI code (for now) and possibly from other platform-specific forms of sleeping (in the indefinite future). Points without consensus: * jkim thinks we should prevent suspend when we're dropping to single-user mode; I'm not sure I see the point, but I don't think there's any harm in doing that too. * Ian Smith would like to have suspend blocked for the last 5 minutes before shutdown(8) signals init to shut the system down. I don't think anyone else has expressed a desire for this, and some people have raised concerns about blocking suspend for too long in case a system is running out of battery; so I'm inclined to leave this out at this point. (It would be easy enough to add the sysctl-frobbing to shutdown(8) if desired later.) With the above in mind, I've written (but not yet actually compiled or tested, so beware of typos) a patch which I think makes sense. If nobody is violently opposed to this I'll make sure I got the details right and then commit this in a few days. -- Colin Percival Security Officer Emeritus, FreeBSD | The power to serve Founder, Tarsnap | www.tarsnap.com | Online backups for the truly paranoid --------------050603020603000908060907 Content-Type: text/x-patch; name="block_suspend.patch" Content-Transfer-Encoding: 7bit Content-Disposition: attachment; filename="block_suspend.patch" Index: sbin/init/init.c =================================================================== --- sbin/init/init.c (revision 288249) +++ sbin/init/init.c (working copy) @@ -1481,6 +1481,16 @@ } /* + * Block (if block == 1) or unblock (if block == 0) suspend. + */ +static void +block_suspend(int block) +{ + + sysctlbyname("kern.suspend_blocked", NULL, NULL, &block, sizeof(block)); +} + +/* * Bring the system down to single user. */ static state_func_t @@ -1487,7 +1497,16 @@ death(void) { session_t *sp; + int block, blocked; + size_t len; + /* Temporarily block suspend. */ + len = sizeof(blocked); + block = 1; + if (sysctlbyname("kern.suspend_blocked", &blocked, &len, + &block, sizeof(block))) + blocked = 0; + /* * Also revoke the TTY here. Because runshutdown() may reopen * the TTY whose getty we're killing here, there is no guarantee @@ -1503,6 +1522,11 @@ /* Try to run the rc.shutdown script within a period of time */ runshutdown(); + /* Unblock suspend if we blocked it. */ + if (!blocked) + sysctlbyname(kern.suspend_blocked", NULL, NULL, + &blocked, sizeof(blocked)); + return (state_func_t) death_single; } Index: sys/dev/acpica/acpi.c =================================================================== --- sys/dev/acpica/acpi.c (revision 288249) +++ sys/dev/acpica/acpi.c (working copy) @@ -2574,8 +2574,11 @@ if (!acpi_sleep_states[state]) return (EOPNOTSUPP); - /* If a suspend request is already in progress, just return. */ - if (sc->acpi_next_sstate != 0) { + /* + * If a reboot/shutdown/suspend request is already in progress or + * suspend is blocked due to an upcoming shutdown, just return. + */ + if (rebooting || sc->acpi_next_sstate != 0 || suspend_blocked) { return (0); } Index: sys/kern/kern_shutdown.c =================================================================== --- sys/kern/kern_shutdown.c (revision 288249) +++ sys/kern/kern_shutdown.c (working copy) @@ -137,6 +137,10 @@ SYSCTL_INT(_kern_shutdown, OID_AUTO, show_busybufs, CTLFLAG_RW, &show_busybufs, 0, ""); +int suspend_blocked = 0; +SYSCTL_INT(_kern, OID_AUTO, suspend_blocked, CTLFLAG_RW, + &suspend_blocked, 0, "Block suspend due to a pending shutdown"); + /* * Variable panicstr contains argument to first call to panic; used as flag * to indicate that the kernel has already called panic. Index: sys/sys/systm.h =================================================================== --- sys/sys/systm.h (revision 288249) +++ sys/sys/systm.h (working copy) @@ -46,6 +46,7 @@ #include <sys/stdint.h> /* for people using printf mainly */ extern int cold; /* nonzero if we are doing a cold boot */ +extern int suspend_blocked; /* block suspend due to pending shutdown */ extern int rebooting; /* kern_reboot() has been called. */ extern const char *panicstr; /* panic message */ extern char version[]; /* system version */ --------------050603020603000908060907--
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