lkml.org 
[lkml]   [2013]   [Sep]   [20]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    From
    SubjectRe: [PATCH v2 3/3] ACPI / video: Do not register backlight if win8 and native interface exists
    Date
    On Tue, 17 Sep 2013, Aaron Lu <aaron.lu@intel.com> 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.
    >
    > This patch is an evolution from previous work done by Matthew Garrett,
    > Chun-Yi Lee, Seth Forshee and Rafael J. Wysocki.
    >
    > Signed-off-by: Aaron Lu <aaron.lu@intel.com>
    > ---
    > drivers/acpi/internal.h | 5 ++---
    > drivers/acpi/video.c | 27 +++++----------------------
    > drivers/acpi/video_detect.c | 14 ++++++++++++--
    > 3 files changed, 19 insertions(+), 27 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 5ad5a71..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;
    > @@ -1677,23 +1677,6 @@ static int acpi_video_bus_unregister_backlight(struct acpi_video_bus *video)
    > return error;
    > }
    >
    > -int acpi_video_unregister_backlight(void)
    > -{
    > - struct acpi_video_bus *video;
    > - int error = 0;
    > -
    > - mutex_lock(&video_list_lock);
    > - list_for_each_entry(video, &video_bus_head, entry) {
    > - error = acpi_video_bus_unregister_backlight(video);
    > - if (error)
    > - break;
    > - }
    > - mutex_unlock(&video_list_lock);
    > -
    > - return error;
    > -}
    > -EXPORT_SYMBOL(acpi_video_unregister_backlight);

    You add this in patch 2/3 only to remove it again in 3/3?

    > -
    > static void acpi_video_dev_add_notify_handler(struct acpi_video_device *device)
    > {
    > acpi_status status;
    > 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 <linux/acpi.h>
    > #include <linux/dmi.h>
    > #include <linux/pci.h>
    > +#include <linux/backlight.h>
    >
    > #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;
    > + return acpi_video_backlight_support();
    > +}

    IIUC this expects the raw backlight device to have been registered prior
    to calling acpi_video_register(). This only works for i915 which calls
    acpi_video_register() itself.


    BR,
    Jani.



    > +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.
    > --
    > 1.8.4.12.g2ea3df6
    >

    --
    Jani Nikula, Intel Open Source Technology Center


    \
     
     \ /
      Last update: 2013-09-20 11:01    [W:5.723 / U:0.056 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site