From mboxrd@z Thu Jan 1 00:00:00 1970 From: Takashi Iwai Subject: Re: [REGRESSION 4.17] Spurious wakeup / reboot with power button Date: Thu, 05 Jul 2018 11:50:11 +0200 Message-ID: References: Mime-Version: 1.0 (generated by SEMI 1.14.6 - "Maruoka") Content-Type: text/plain; charset=US-ASCII Return-path: In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org To: "Rafael J. Wysocki" Cc: "Rafael J. Wysocki" , Thomas =?UTF-8?B?SMOkbmln?= , Linux PM , Linux Kernel Mailing List List-Id: linux-pm@vger.kernel.org On Thu, 05 Jul 2018 11:34:59 +0200, Rafael J. Wysocki wrote: > > Hi, > > On Thu, Jul 5, 2018 at 9:05 AM, Takashi Iwai wrote: > > Hi, > > > > we've got a regression report since 4.17 about the behavior of > > power-off with the power button. When a machine is powered off with > > the power button on desktop, it reboots after a few seconds instead of > > power down. > > > > The manual power down via "systemctl poweroff" works fine, so it's > > possibly some spurious wakeup by the power button action, and some > > ACPI-related change is suspected. > > The regression still remains in 4.18-rc3. > > There are only a few ACPI commits directly related to power management > between 4.16 and 4.17 and none of them looks particularly suspicious. OK, interesting. > It looks like the power button state may not be cleared sufficiently > after it's been pressed which is now visible for some reason. Hmm, where can such a state remain? Since it happens after the machine turned off, some (ACPI) wakeup bits? > How does the button poweroff work, exactly? I guess the event is > collected by a user space demon which then triggers power of via sysfs > or similar? Usually X desktop environment receives an input event from the ACPI power button input device, and deals the event accordingly depending on the setup. The power-down behavior itself should be equivalent with "systemctl poweroff" or such. thanks, Takashi