From mboxrd@z Thu Jan 1 00:00:00 1970 From: Aaron Lu Subject: Re: [PATCH] acpi: video: no automatic brightness changes by firmware Date: Mon, 17 Jun 2013 23:01:50 +0800 Message-ID: <51BF24DE.7090906@intel.com> References: <51B98CFD.7090409@intel.com> <51BE5FD6.6070405@intel.com> <29837409.i8Bi9MdLJI@vostro.rjw.lan> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: Received: from mga02.intel.com ([134.134.136.20]:42967 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752237Ab3FQPBl (ORCPT ); Mon, 17 Jun 2013 11:01:41 -0400 In-Reply-To: <29837409.i8Bi9MdLJI@vostro.rjw.lan> Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: "Rafael J. Wysocki" Cc: Len Brown , ACPI Devel Mailing List , Zhang Rui , Micael Dias , Dan Garton , Bob Ziuchkovski On 06/17/2013 07:27 PM, Rafael J. Wysocki wrote: > On Monday, June 17, 2013 09:01:10 AM Aaron Lu wrote: >> Starting from win8, MS backlight control driver will set bit 2 of the >> parameter of control method _DOS, to inform firmware it should not >> perform any automatic brightness changes. This mostly affects hotkey >> notification deliver - if we do not set this bit, on hotkey press, >> firmware may choose to adjust brightness level instead of sending out >> notification and doing nothing. >> >> So this patch sets bit 2 when calling _DOS so that GUIs can show the >> notification window on hotkey press. >> >> The MS document on win8 backlight control is here: >> http://msdn.microsoft.com/en-US/library/windows/hardware/jj159305 >> >> This patch solves problem for ASUS N56VZ and ASUS N56VJ, both for >> notification delivery and for brightness control. >> >> Buglink: https://bugzilla.kernel.org/show_bug.cgi?id=52951 >> Buglink: https://bugzilla.kernel.org/show_bug.cgi?id=56711 >> Reported-and-tested-by: Micael Dias >> Reported-and-tested-by: Dan Garton >> Reported-and-tested-by: Bob Ziuchkovski >> Signed-off-by: Aaron Lu > > OK, do we need that in -stable and if so, which ones? Perhaps only for new kernels, since 3.7 and 3.8 are EOL-ed, so just for 3.9. I don't think older kernels need change the behavior. Thanks, Aaron > > Rafael > > >> --- >> drivers/acpi/video.c | 4 ++-- >> 1 file changed, 2 insertions(+), 2 deletions(-) >> >> diff --git a/drivers/acpi/video.c b/drivers/acpi/video.c >> index b8299f2..f8fa541 100644 >> --- a/drivers/acpi/video.c >> +++ b/drivers/acpi/video.c >> @@ -1543,12 +1543,12 @@ static int acpi_video_bus_put_devices(struct acpi_video_bus *video) >> >> static int acpi_video_bus_start_devices(struct acpi_video_bus *video) >> { >> - return acpi_video_bus_DOS(video, 0, 0); >> + return acpi_video_bus_DOS(video, 0, 1); >> } >> >> static int acpi_video_bus_stop_devices(struct acpi_video_bus *video) >> { >> - return acpi_video_bus_DOS(video, 0, 1); >> + return acpi_video_bus_DOS(video, 0, 0); >> } >> >> static void acpi_video_bus_notify(struct acpi_device *device, u32 event) >>