From mboxrd@z Thu Jan 1 00:00:00 1970 From: Hans de Goede Subject: [PATCH 2/4] acpi-video: Add an acpi_video_unregister_backlight function Date: Thu, 15 May 2014 13:22:34 +0200 Message-ID: <1400152956-9053-3-git-send-email-hdegoede@redhat.com> References: <1400152956-9053-1-git-send-email-hdegoede@redhat.com> Return-path: Received: from mx1.redhat.com ([209.132.183.28]:56442 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752616AbaEOLW5 (ORCPT ); Thu, 15 May 2014 07:22:57 -0400 In-Reply-To: <1400152956-9053-1-git-send-email-hdegoede@redhat.com> Sender: linux-acpi-owner@vger.kernel.org List-Id: linux-acpi@vger.kernel.org To: Lee Chun-Yi , Aaron Lu Cc: Zhang Rui , "Rafael J. Wysocki" , Len Brown , Matthew Garrett , Massimiliano , linux-acpi@vger.kernel.org, platform-driver-x86@vger.kernel.org, Hans de Goede Add an acpi_video_unregister_backlight function, which only unregisters the backlight device, and leaves the acpi_notifier in place. Some acpi_vendor driver need this as they don't want the acpi_video# backlight device, but do need the acpi-video driver for hotkey handling. Chances are that this new acpi_video_unregister_backlight() is actually what existing acpi_vendor drivers have wanted all along. Currently acpi_vendor drivers which want to disable the acpi_video# backlight device, make 2 calls: acpi_video_dmi_promote_vendor(); acpi_video_unregister(); The intention here is to make things independent of when acpi_video_register() gets called. As acpi_video_register() will get called on acpi-video load time on non intel gfx machines, while it gets called on i915 load time on intel gfx machines. This leads to the following 2 interesting scenarios: a) intel gfx: 1) acpi-video module gets loaded (as it is a dependency of acpi_vendor and i915) 2) acpi-video does NOT call acpi_video_register() 3) acpi_vendor loads (lets assume it loads before i915), calls acpi_video_dmi_promote_vendor(); which sets ACPI_VIDEO_BACKLIGHT_DMI_VENDOR 4) calls acpi_video_unregister -> not registered, nop 5) i915 loads, calls acpi_video_register 6) acpi_video_register registers the acpi_notifier for the hotkeys, does NOT register a backlight device because of ACPI_VIDEO_BACKLIGHT_DMI_VENDOR b) non intel gfx 1) acpi-video module gets loaded (as it is a dependency acpi_vendor) 2) acpi-video calls acpi_video_register() 3) acpi_video_register registers the acpi_notifier for the hotkeys, and a backlight device 4) acpi_vendor loads, calls acpi_video_dmi_promote_vendor() 5) calls acpi_video_unregister, this unregisters BOTH the acpi_notifier for the hotkeys AND the backlight device So here we have possibly the same acpi_vendor module, making the same calls, but with different results, in one cases acpi-video does handle hotkeys, in the other it does not. Note that the a) scenario turns into b) if we assume the i915 module loads before the vendor_acpi module, so we also have different behavior depending on module loading order! So as said I believe that quite a few existing acpi_vendor modules really always want the behavior of a), hence this patch adds a new acpi_video_unregister_backlight() which gives the behavior of a) independent of module loading order. Signed-off-by: Hans de Goede --- drivers/acpi/video.c | 14 ++++++++++++++ include/acpi/video.h | 2 ++ 2 files changed, 16 insertions(+) diff --git a/drivers/acpi/video.c b/drivers/acpi/video.c index f767eba..898b084 100644 --- a/drivers/acpi/video.c +++ b/drivers/acpi/video.c @@ -2182,6 +2182,20 @@ void acpi_video_unregister(void) } EXPORT_SYMBOL(acpi_video_unregister); +void acpi_video_unregister_backlight(void) +{ + struct acpi_video_bus *video; + + if (!register_count) + return; + + mutex_lock(&video_list_lock); + list_for_each_entry(video, &video_bus_head, entry) + acpi_video_bus_unregister_backlight(video); + mutex_unlock(&video_list_lock); +} +EXPORT_SYMBOL(acpi_video_unregister_backlight); + /* * This is kind of nasty. Hardware using Intel chipsets may require * the video opregion code to be run first in order to initialise diff --git a/include/acpi/video.h b/include/acpi/video.h index 61109f2..4722c06 100644 --- a/include/acpi/video.h +++ b/include/acpi/video.h @@ -19,11 +19,13 @@ struct acpi_device; #if (defined CONFIG_ACPI_VIDEO || defined CONFIG_ACPI_VIDEO_MODULE) extern int acpi_video_register(void); extern void acpi_video_unregister(void); +extern void acpi_video_unregister_backlight(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 void acpi_video_unregister(void) { return; } +extern inline void acpi_video_unregister_backlight(void); { return; } static inline int acpi_video_get_edid(struct acpi_device *device, int type, int device_id, void **edid) { -- 1.9.0