| Message ID | 1400316483-6356-2-git-send-email-hdegoede@redhat.com (mailing list archive) |
|---|---|
| State | Accepted, archived |
| Headers | show |
On 05/17/2014 04:48 PM, Hans de Goede wrote: > 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 <hdegoede@redhat.com> Reviewed-by: Aaron Lu <aaron.lu@intel.com> Thanks, Aaron > --- > 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 52176ad..ba6e4d7 100644 > --- a/drivers/acpi/video.c > +++ b/drivers/acpi/video.c > @@ -2166,6 +2166,20 @@ 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..ea4c7bb 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; } > +static 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) > { > -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/drivers/acpi/video.c b/drivers/acpi/video.c index 52176ad..ba6e4d7 100644 --- a/drivers/acpi/video.c +++ b/drivers/acpi/video.c @@ -2166,6 +2166,20 @@ 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..ea4c7bb 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; } +static 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) {
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 <hdegoede@redhat.com> --- drivers/acpi/video.c | 14 ++++++++++++++ include/acpi/video.h | 2 ++ 2 files changed, 16 insertions(+)