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: Wed, 17 Jul 2013 14:27:21 +0800 Message-ID: <51E63949.10705@intel.com> References: <51B98CFD.7090409@intel.com> <51BE5FD6.6070405@intel.com> <20130617224040.GB14793@srcf.ucam.org> <51BFA628.8000804@intel.com> <51D61E3B.2000205@intel.com> <51E4D535.10009@intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Return-path: Received: from mga14.intel.com ([143.182.124.37]:31918 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751330Ab3GQG0k (ORCPT ); Wed, 17 Jul 2013 02:26:40 -0400 In-Reply-To: Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: Micael Cc: "Rafael J. Wysocki" , Matthew Garrett , Len Brown , ACPI Devel Mailing List , Zhang Rui , Dan Garton , Bob Ziuchkovski On 07/16/2013 10:39 PM, Micael wrote: > Working fine here. Thanks for your testing! -Aaron > > > On Tue, Jul 16, 2013 at 6:08 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. This behavior change is only >> necessary for win8 systems. >> >> The MS document on win8 backlight control is here: >> http://msdn.microsoft.com/en-US/library/windows/hardware/jj159305 >> >> Buglink: https://bugzilla.kernel.org/show_bug.cgi?id=52951 >> Buglink: https://bugzilla.kernel.org/show_bug.cgi?id=56711 >> Reported-by: Micael Dias >> Reported-by: Dan Garton >> Reported-by: Bob Ziuchkovski >> Signed-off-by: Aaron Lu >> --- >> Apply on top of: >> https://patchwork.kernel.org/patch/2812951/ (expose OSI version) >> https://patchwork.kernel.org/patch/2827793/ (win8 video quirk) >> >> Micael, Dan and Bob, >> Please give the patch a test if possible, thanks. >> >> v2: Make the behavior change only for win8 systems; use the newly added >> function acpi_video_backlight_quirks as the condition check for win8. >> >> drivers/acpi/video.c | 10 ++++++++-- >> 1 file changed, 8 insertions(+), 2 deletions(-) >> >> diff --git a/drivers/acpi/video.c b/drivers/acpi/video.c >> index 01b1a25..bc2954b 100644 >> --- a/drivers/acpi/video.c >> +++ b/drivers/acpi/video.c >> @@ -1534,14 +1534,20 @@ static int acpi_video_bus_put_devices(struct >> acpi_video_bus *video) >> >> /* acpi_video interface */ >> >> +/* >> + * Win8 requires setting bit2 of _DOS to let firmware know it shouldn't >> + * preform any automatic brightness change on receiving a notification. >> + */ >> 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, >> + acpi_video_backlight_quirks() ? 1 : 0); >> } >> >> 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, >> + acpi_video_backlight_quirks() ? 0 : 1); >> } >> >> static void acpi_video_bus_notify(struct acpi_device *device, u32 event) >> -- >> 1.8.3.2.10.g43d11f4 >> > > >