From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Message-Id: <20120316233447.994935619@linuxfoundation.org> Date: Fri, 16 Mar 2012 16:34:55 -0700 From: Greg KH To: linux-kernel@vger.kernel.org, stable@vger.kernel.org Cc: torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Alan Stern , "Rafael J. Wysocki" , Kostyantyn Shlyakhovoy Subject: [ 08/38] PM / Driver core: leave runtime PM enabled during system shutdown In-Reply-To: <20120316233422.GA5461@kroah.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: 3.0-stable review patch. If anyone has any objections, please let me know. ------------------ From: Alan Stern commit fe6b91f47080eb17d21cbf2a39311877d57f6938 upstream. Disabling all runtime PM during system shutdown turns out not to be a good idea, because some devices may need to be woken up from a low-power state at that time. The whole point of disabling runtime PM for system shutdown was to prevent untimely runtime-suspend method calls. This patch (as1504) accomplishes the same result by incrementing the usage count for each device and waiting for ongoing runtime-PM callbacks to finish. This is what we already do during system suspend and hibernation, which makes sense since the shutdown method is pretty much a legacy analog of the pm->poweroff method. This fixes a recent regression on some OMAP systems introduced by commit af8db1508f2c9f3b6e633e2d2d906c6557c617f9 (PM / driver core: disable device's runtime PM during shutdown). Reported-and-tested-by: NeilBrown Signed-off-by: Alan Stern Acked-by: Greg Kroah-Hartman Signed-off-by: Rafael J. Wysocki Cc: Kostyantyn Shlyakhovoy Signed-off-by: Greg Kroah-Hartman --- drivers/base/core.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -1743,8 +1743,10 @@ void device_shutdown(void) */ list_del_init(&dev->kobj.entry); spin_unlock(&devices_kset->list_lock); - /* Disable all device's runtime power management */ - pm_runtime_disable(dev); + + /* Don't allow any more runtime suspends */ + pm_runtime_get_noresume(dev); + pm_runtime_barrier(dev); if (dev->bus && dev->bus->shutdown) { dev_dbg(dev, "shutdown\n");