From mboxrd@z Thu Jan 1 00:00:00 1970 From: Aaron Lu Subject: Re: [PATCH 3/3] i915: Don't provide ACPI backlight interface if firmware expects Windows 8 Date: Mon, 08 Jul 2013 16:00:16 +0800 Message-ID: <51DA7190.6080208@gmail.com> References: <1370818899-8595-1-git-send-email-matthew.garrett@nebula.com> <51D7AF14.9050508@gmail.com> <3467567.zOLDhye8QD@vostro.rjw.lan> <12270512.1rshgKaUug@vostro.rjw.lan> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Return-path: Received: from mail-pa0-f44.google.com ([209.85.220.44]:53313 "EHLO mail-pa0-f44.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751453Ab3GHH7n (ORCPT ); Mon, 8 Jul 2013 03:59:43 -0400 In-Reply-To: <12270512.1rshgKaUug@vostro.rjw.lan> Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: "Rafael J. Wysocki" Cc: Matthew Garrett , daniel.vetter@ffwll.ch, linux-acpi@vger.kernel.org, seth.forshee@canonical.com, joeyli.kernel@gmail.com, intel-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org, lenb@kernel.org On 07/07/2013 09:19 PM, Rafael J. Wysocki wrote: > OK, the patch is appended. Please have a look and tell me what you think. > > Thanks, > Rafael > > > --- > From: Rafael J. Wysocki > Subject: ACPI / video / i915: Remove ACPI backlight if firmware expects Windows 8 > > 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". > > There's a problem with that approach, however, because simply > avoiding to register the ACPI backlight interface if the firmware > calls _OSI for Windows 8 may not work in the following situations: > (1) The ACPI backlight interface actually works on the given system > and the i915 driver is not loaded (e.g. another graphics driver > is used). > (2) The ACPI backlight interface doesn't work on the given system, > but there is a vendor platform driver that will register its > own, equally broken, backlight interface if the ACPI one is not > registered in advance. The condition thinkpad_acpi checks to decide if it wants to create backlight control interface is acpi_video_backlight_support function, not that if ACPI video driver has registered previously. I'm sorry if my previous words gave you such a conclusion. > Therefore we need to keep the ACPI backlight interface registered > until the i915 driver is loaded which then will unregister it if > the firmware has called _OSI for Windows 8. > > For this reason, introduce an alternative function for registering > ACPI video, acpi_video_register_with_quirks(), that will check > whether or not the ACPI video driver has already been registered > and whether or not the backlight Windows 8 quirk has to be applied. > If the quirk has to be applied, it will block the ACPI backlight > support and either unregister the backlight interface if the ACPI > video driver has already been registered, or register the ACPI > video driver without the backlight interface otherwise. Make > the i915 driver use acpi_video_register_with_quirks() instead of > acpi_video_register() in i915_driver_load(). > > This change is based on earlier patches from Matthew Garrett, > Chun-Yi Lee and Seth Forshee. > > Signed-off-by: Rafael J. Wysocki > --- > drivers/acpi/video.c | 61 ++++++++++++++++++++++++++++++++++++---- > drivers/acpi/video_detect.c | 11 +++++++ > drivers/gpu/drm/i915/i915_dma.c | 2 - > include/acpi/video.h | 11 ++++++- > include/linux/acpi.h | 6 +++ > 5 files changed, 84 insertions(+), 7 deletions(-) > > Index: linux-pm/drivers/acpi/video.c > =================================================================== > --- linux-pm.orig/drivers/acpi/video.c > +++ linux-pm/drivers/acpi/video.c > @@ -1854,6 +1854,46 @@ static int acpi_video_bus_remove(struct > return 0; > } > > +static acpi_status video_unregister_backlight(acpi_handle handle, u32 lvl, > + void *context, void **rv) > +{ > + struct acpi_device *acpi_dev; > + struct acpi_video_bus *video; > + struct acpi_video_device *dev, *next; > + > + if (acpi_bus_get_device(handle, &acpi_dev)) > + return AE_OK; > + > + if (acpi_match_device_ids(acpi_dev, video_device_ids)) > + return AE_OK; > + > + video = acpi_driver_data(acpi_dev); > + if (!video) > + return AE_OK; > + > + acpi_video_bus_stop_devices(video); > + mutex_lock(&video->device_list_lock); > + list_for_each_entry_safe(dev, next, &video->video_device_list, entry) { > + if (dev->backlight) { > + backlight_device_unregister(dev->backlight); > + dev->backlight = NULL; > + kfree(dev->brightness->levels); > + kfree(dev->brightness); > + } > + if (dev->cooling_dev) { > + sysfs_remove_link(&dev->dev->dev.kobj, > + "thermal_cooling"); > + sysfs_remove_link(&dev->cooling_dev->device.kobj, > + "device"); > + thermal_cooling_device_unregister(dev->cooling_dev); > + dev->cooling_dev = NULL; > + } > + } > + mutex_unlock(&video->device_list_lock); > + acpi_video_bus_start_devices(video); > + return AE_OK; > +} > + > static int __init is_i740(struct pci_dev *dev) > { > if (dev->device == 0x00D1) > @@ -1885,14 +1925,25 @@ static int __init intel_opregion_present > return opregion; > } > > -int acpi_video_register(void) > +int __acpi_video_register(bool backlight_quirks) > { > - int result = 0; > + bool no_backlight; > + int result; > + > + no_backlight = backlight_quirks ? acpi_video_backlight_quirks() : false; > + > if (register_count) { > /* > - * if the function of acpi_video_register is already called, > - * don't register the acpi_vide_bus again and return no error. > + * If acpi_video_register() has been called already, don't try > + * to register acpi_video_bus, but unregister backlight devices > + * if no backlight support is requested. > */ > + if (no_backlight) > + acpi_walk_namespace(ACPI_TYPE_DEVICE, ACPI_ROOT_OBJECT, > + ACPI_UINT32_MAX, > + video_unregister_backlight, > + NULL, NULL, NULL); > + > return 0; > } > > @@ -1908,7 +1959,7 @@ int acpi_video_register(void) > > return 0; > } > -EXPORT_SYMBOL(acpi_video_register); > +EXPORT_SYMBOL(__acpi_video_register); > > void acpi_video_unregister(void) > { > Index: linux-pm/drivers/gpu/drm/i915/i915_dma.c > =================================================================== > --- linux-pm.orig/drivers/gpu/drm/i915/i915_dma.c > +++ linux-pm/drivers/gpu/drm/i915/i915_dma.c > @@ -1660,7 +1660,7 @@ int i915_driver_load(struct drm_device * > if (INTEL_INFO(dev)->num_pipes) { > /* Must be done after probing outputs */ > intel_opregion_init(dev); > - acpi_video_register(); > + acpi_video_register_with_quirks(); > } > > if (IS_GEN5(dev)) > Index: linux-pm/include/acpi/video.h > =================================================================== > --- linux-pm.orig/include/acpi/video.h > +++ linux-pm/include/acpi/video.h > @@ -17,12 +17,21 @@ struct acpi_device; > #define ACPI_VIDEO_DISPLAY_LEGACY_TV 0x0200 > > #if (defined CONFIG_ACPI_VIDEO || defined CONFIG_ACPI_VIDEO_MODULE) > -extern int acpi_video_register(void); > +extern int __acpi_video_register(bool backlight_quirks); > +static inline int acpi_video_register(void) > +{ > + return __acpi_video_register(false); > +} > +static inline int acpi_video_register_with_quirks(void) > +{ > + return __acpi_video_register(true); > +} > extern void acpi_video_unregister(void); > extern int acpi_video_get_edid(struct acpi_device *device, int type, > int device_id, void **edid); > #else > static inline int acpi_video_register(void) { return 0; } > +static inline int acpi_video_register_with_quirks(void) { return 0; } > static inline void acpi_video_unregister(void) { return; } > static inline int acpi_video_get_edid(struct acpi_device *device, int type, > int device_id, void **edid) > Index: linux-pm/drivers/acpi/video_detect.c > =================================================================== > --- linux-pm.orig/drivers/acpi/video_detect.c > +++ linux-pm/drivers/acpi/video_detect.c > @@ -234,6 +234,17 @@ static void acpi_video_caps_check(void) > acpi_video_get_capabilities(NULL); > } > > +bool acpi_video_backlight_quirks(void) > +{ > + if (acpi_gbl_osi_data >= ACPI_OSI_WIN_8) { > + acpi_video_caps_check(); > + acpi_video_support |= ACPI_VIDEO_BACKLIGHT_FORCE_VENDOR; If the ACPI_VIDEO_BACKLIGHT_FORCE_VENDOR flag is set, acpi_video_backlight_support will return 0, thinkpad_acpi will create backlight interface for the system, which is not what we want. Thanks, Aaron > + return true; > + } > + return false; > +} > +EXPORT_SYMBOL(acpi_video_backlight_quirks); > + > /* Promote the vendor interface instead of the generic video module. > * This function allow DMI blacklists to be implemented by externals > * platform drivers instead of putting a big blacklist in video_detect.c > Index: linux-pm/include/linux/acpi.h > =================================================================== > --- linux-pm.orig/include/linux/acpi.h > +++ linux-pm/include/linux/acpi.h > @@ -196,6 +196,7 @@ extern bool wmi_has_guid(const char *gui > > extern long acpi_video_get_capabilities(acpi_handle graphics_dev_handle); > extern long acpi_is_video_device(acpi_handle handle); > +extern bool acpi_video_backlight_quirks(void); > extern void acpi_video_dmi_promote_vendor(void); > extern void acpi_video_dmi_demote_vendor(void); > extern int acpi_video_backlight_support(void); > @@ -213,6 +214,11 @@ static inline long acpi_is_video_device( > return 0; > } > > +static inline bool acpi_video_backlight_quirks(void) > +{ > + return false; > +} > + > static inline void acpi_video_dmi_promote_vendor(void) > { > } >