From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Rafael J. Wysocki" Subject: Re: 4.5 regression: ACPI hangs when backlight hotkeys are pressed Date: Tue, 19 Jan 2016 01:20:22 +0100 Message-ID: <13973280.p4fhCg3bGF@vostro.rjw.lan> References: <1541559.QSyCfx8pKj@vostro.rjw.lan> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7Bit Return-path: Received: from v094114.home.net.pl ([79.96.170.134]:59994 "HELO v094114.home.net.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with SMTP id S1754668AbcASATl (ORCPT ); Mon, 18 Jan 2016 19:19:41 -0500 In-Reply-To: Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: Andy Lutomirski Cc: Andy Lutomirski , Linux ACPI , Adrien Schildknecht , Hans de Goede , "Rafael J. Wysocki" On Monday, January 18, 2016 04:09:27 PM Andy Lutomirski wrote: > On Mon, Jan 18, 2016 at 4:01 PM, Rafael J. Wysocki wrote: > > On Monday, January 18, 2016 03:57:49 PM Andy Lutomirski wrote: > >> On Mon, Jan 18, 2016 at 3:54 PM, Rafael J. Wysocki wrote: > >> > On Monday, January 18, 2016 03:04:28 PM Andy Lutomirski wrote: > >> >> On Mon, Jan 18, 2016 at 2:25 PM, Rafael J. Wysocki wrote: > >> >> > On Monday, January 18, 2016 12:52:53 PM Andy Lutomirski wrote: > >> >> >> I'm running 4.4 with the pm+acpi-4.5-rc1-1 merged in. After pressing > >> >> >> the backlight hotkeys a couple times, things start to break. Poking > >> >> >> at hung thread stacks, it appears that calls to > >> >> >> acpi_video_handles_brightness_key_presses never return. > >> >> >> > >> >> >> It appears that the culprit is: > >> >> >> > >> >> >> commit aecbd9b1bff6afbe349921b406b99d285b412820 > >> >> >> Author: Adrien Schildknecht > >> >> >> Date: Mon Jan 4 23:22:28 2016 +0100 > >> >> >> > >> >> >> ACPI / video: driver must be registered before checking for keypresses > >> >> >> > >> >> >> Reverting that patch makes my laptop work again. > >> >> >> > >> >> >> I don't know what that patch is trying to do, but it looks highly > >> >> >> questionable to me. Why should an accessor wait for a potential > >> >> >> different driver to register something? I see no guarantee that it > >> >> >> will eve happen. > >> >> >> > >> >> >> This is a Dell XPS 13 9350. > >> >> > > >> >> > Should be fixed in my linux-next branch, can you please try that one? > >> >> > > >> >> > >> >> To avoid churning my laptop tree too much, I cherry-picked: > >> >> > >> >> ACPI / video: Add disable_backlight_sysfs_if quirk for the Toshiba > >> >> Satellite R830 > >> >> ACPI / video: Revert "thinkpad_acpi: Use > >> >> acpi_video_handles_brightness_key_presses()" > >> >> ACPI / video: Document acpi_video_handles_brightness_key_presses() a bit > >> >> ACPI / video: Fix using an uninitialized mutex / list_head in > >> >> acpi_video_handles_brightness_key_presses() > >> >> ACPI / video: Revert "ACPI / video: driver must be registered before > >> >> checking for keypresses" > >> >> > >> >> The result seems to work. Are you planning on sending these for 4.5? > >> > > >> > Yes, I am. > >> > > >> > Most likely on Wednesday (or Thursday if anything urgent shows up in the meantime). > >> > > >> > >> Sounds good. I'll keep testing. > >> > >> Some day my laptop will Just Work on a distro kernel :) > > > > Well, even then it'll help a lot if you run the mainline on it, so we know that > > it doesn't regress. > > > > So far the only other change I noticed is that I stopped seeing > warnings about S1 and S2 being missing. That's intentional. :-) Thanks, Rafael