Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757193Ab3JJARt (ORCPT ); Wed, 9 Oct 2013 20:17:49 -0400 Received: from hydra.sisk.pl ([212.160.235.94]:50529 "EHLO hydra.sisk.pl" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754640Ab3JJARr (ORCPT ); Wed, 9 Oct 2013 20:17:47 -0400 From: "Rafael J. Wysocki" To: Aaron Lu Cc: linux-acpi@vger.kernel.org, intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, Daniel Vetter , Matthew Garrett , Seth Forshee , Lee Chun-Yi , Richard Purdie , Igor Gnatenko , Yves-Alexis Perez , Felipe Contreras , Jani Nikula , Ben Jencks , Steven Newbury , James Hogan , Kamal Mostafa , Joerg Platte , Kalle Valo , Martin Steigerwald , =?ISO-8859-1?Q?J=F6rg?= Otte , Mike Galbraith , platform-driver-x86@vger.kernel.org, Mika Westerberg , Henrique de Moraes Holschuh Subject: Re: [PATCH v4 3/4] ACPI / video: Do not register backlight if win8 and native interface exists Date: Thu, 10 Oct 2013 02:29:22 +0200 Message-ID: <9897358.0Z0t2PgJOe@vostro.rjw.lan> User-Agent: KMail/4.10.5 (Linux/3.11.0+; KDE/4.10.5; x86_64; ; ) In-Reply-To: <1381214401-24672-4-git-send-email-aaron.lu@intel.com> References: <1381214401-24672-1-git-send-email-aaron.lu@intel.com> <1381214401-24672-4-git-send-email-aaron.lu@intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="utf-8" Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5372 Lines: 138 On Tuesday, October 08, 2013 02:40:00 PM Aaron Lu wrote: > According to Matthew Garrett, "Windows 8 leaves backlight control up > to individual graphics drivers rather than making ACPI calls itself. > There's plenty of evidence to suggest that the Intel driver for > Windows [8] doesn't use the ACPI interface, including the fact that > it's broken on a bunch of machines when the OS claims to support > Windows 8. The simplest thing to do appears to be to disable the > ACPI backlight interface on these systems". > > So for Win8 systems, if there is native backlight control interface > registered by GPU driver, ACPI video will not register its own. For > users who prefer to keep ACPI video's backlight interface, the existing > kernel cmdline option acpi_backlight=video can be used. > > Signed-off-by: Aaron Lu > Tested-by: Igor Gnatenko > Tested-by: Yves-Alexis Perez > Tested-by: Mika Westerberg > --- > drivers/acpi/internal.h | 5 ++--- > drivers/acpi/video.c | 10 +++++----- > drivers/acpi/video_detect.c | 14 ++++++++++++-- > 3 files changed, 19 insertions(+), 10 deletions(-) > > diff --git a/drivers/acpi/internal.h b/drivers/acpi/internal.h > index 20f4233..453ae8d 100644 > --- a/drivers/acpi/internal.h > +++ b/drivers/acpi/internal.h > @@ -169,9 +169,8 @@ int acpi_create_platform_device(struct acpi_device *adev, > Video > -------------------------------------------------------------------------- */ > #if defined(CONFIG_ACPI_VIDEO) || defined(CONFIG_ACPI_VIDEO_MODULE) > -bool acpi_video_backlight_quirks(void); > -#else > -static inline bool acpi_video_backlight_quirks(void) { return false; } > +bool acpi_osi_is_win8(void); > +bool acpi_video_verify_backlight_support(void); > #endif > > #endif /* _ACPI_INTERNAL_H_ */ > diff --git a/drivers/acpi/video.c b/drivers/acpi/video.c > index 3bd1eaa..343db59 100644 > --- a/drivers/acpi/video.c > +++ b/drivers/acpi/video.c > @@ -1256,8 +1256,8 @@ acpi_video_switch_brightness(struct acpi_video_device *device, int event) > unsigned long long level_current, level_next; > int result = -EINVAL; > > - /* no warning message if acpi_backlight=vendor is used */ > - if (!acpi_video_backlight_support()) > + /* no warning message if acpi_backlight=vendor or a quirk is used */ > + if (!acpi_video_verify_backlight_support()) > return 0; > > if (!device->brightness) > @@ -1386,13 +1386,13 @@ acpi_video_bus_get_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, > - acpi_video_backlight_quirks() ? 1 : 0); > + acpi_osi_is_win8() ? 1 : 0); > } > > static int acpi_video_bus_stop_devices(struct acpi_video_bus *video) > { > return acpi_video_bus_DOS(video, 0, > - acpi_video_backlight_quirks() ? 0 : 1); > + acpi_osi_is_win8() ? 0 : 1); > } > > static void acpi_video_bus_notify(struct acpi_device *device, u32 event) > @@ -1558,7 +1558,7 @@ acpi_video_bus_match(acpi_handle handle, u32 level, void *context, > > static void acpi_video_dev_register_backlight(struct acpi_video_device *device) > { > - if (acpi_video_backlight_support()) { > + if (acpi_video_verify_backlight_support()) { > struct backlight_properties props; > struct pci_dev *pdev; > acpi_handle acpi_parent; > diff --git a/drivers/acpi/video_detect.c b/drivers/acpi/video_detect.c > index 940edbf..23d7d26 100644 > --- a/drivers/acpi/video_detect.c > +++ b/drivers/acpi/video_detect.c > @@ -37,6 +37,7 @@ > #include > #include > #include > +#include > > #include "internal.h" > > @@ -233,11 +234,11 @@ static void acpi_video_caps_check(void) > acpi_video_get_capabilities(NULL); > } > > -bool acpi_video_backlight_quirks(void) > +bool acpi_osi_is_win8(void) > { > return acpi_gbl_osi_data >= ACPI_OSI_WIN_8; > } > -EXPORT_SYMBOL(acpi_video_backlight_quirks); > +EXPORT_SYMBOL(acpi_osi_is_win8); > > /* Promote the vendor interface instead of the generic video module. > * This function allow DMI blacklists to be implemented by externals > @@ -283,6 +284,15 @@ int acpi_video_backlight_support(void) > } > EXPORT_SYMBOL(acpi_video_backlight_support); > > +bool acpi_video_verify_backlight_support(void) > +{ > + if (!(acpi_video_support & ACPI_VIDEO_BACKLIGHT_FORCE_VIDEO) && > + acpi_osi_is_win8() && backlight_device_registered(BACKLIGHT_RAW)) > + return false; If I'm not mistaken, this will introduce a regression for the people who have problems with the native i915 backlight on Win8-compatible systems. I'd prefer to avoid that at this point. > + return acpi_video_backlight_support(); > +} > +EXPORT_SYMBOL(acpi_video_verify_backlight_support); > + > /* > * Use acpi_backlight=vendor/video to force that backlight switching > * is processed by vendor specific acpi drivers or video.ko driver. Thanks! -- I speak only for myself. Rafael J. Wysocki, Intel Open Source Technology Center. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/