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linux/include/acpi/video.h

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ACPI: Populate DIDL before registering ACPI video device on Intel Intel graphics hardware that implements the ACPI IGD OpRegion spec requires that the list of display devices be populated before any ACPI video methods are called. Detect when this is the case and defer registration until the opregion code calls it. Fixes crashes on HP laptops. http://bugzilla.kernel.org/show_bug.cgi?id=11259 Signed-off-by: Matthew Garrett <mjg@redhat.com> Acked-by: Eric Anholt <eric@anholt.net> Signed-off-by: Len Brown <len.brown@intel.com>
2009-03-19 14:35:39 -07:00
#ifndef __ACPI_VIDEO_H
#define __ACPI_VIDEO_H
#if (defined CONFIG_ACPI_VIDEO || defined CONFIG_ACPI_VIDEO_MODULE)
extern int acpi_video_register(void);
ACPI: Add the reference count to avoid unloading ACPI video bus twice Sometimes both acpi video and i915 driver are compiled as modules. And there exists the strict dependency between the two drivers. The acpi video bus will be unloaded in course of unloading the i915 driver. If we unload the acpi video driver, then the kernel oops will be triggered. Add the reference count to avoid unloading the ACPI video bus twice. The reference count should be checked before unregistering the acpi video bus. If the reference count is already zero, it won't unregister it again. And after the acpi video bus is already unregistered, the reference count will be set to zero. http://bugzilla.kernel.org/show_bug.cgi?id=13396 Signed-off-by: Zhao Yakui <yakui.zhao@intel.com> Acked-by: Zhang Rui <rui.zhang@intel.com> Signed-off-by: Len Brown <len.brown@intel.com>
2009-06-15 20:23:13 -07:00
extern void acpi_video_unregister(void);
ACPI: Populate DIDL before registering ACPI video device on Intel Intel graphics hardware that implements the ACPI IGD OpRegion spec requires that the list of display devices be populated before any ACPI video methods are called. Detect when this is the case and defer registration until the opregion code calls it. Fixes crashes on HP laptops. http://bugzilla.kernel.org/show_bug.cgi?id=11259 Signed-off-by: Matthew Garrett <mjg@redhat.com> Acked-by: Eric Anholt <eric@anholt.net> Signed-off-by: Len Brown <len.brown@intel.com>
2009-03-19 14:35:39 -07:00
#else
static inline int acpi_video_register(void) { return 0; }
ACPI: Add the reference count to avoid unloading ACPI video bus twice Sometimes both acpi video and i915 driver are compiled as modules. And there exists the strict dependency between the two drivers. The acpi video bus will be unloaded in course of unloading the i915 driver. If we unload the acpi video driver, then the kernel oops will be triggered. Add the reference count to avoid unloading the ACPI video bus twice. The reference count should be checked before unregistering the acpi video bus. If the reference count is already zero, it won't unregister it again. And after the acpi video bus is already unregistered, the reference count will be set to zero. http://bugzilla.kernel.org/show_bug.cgi?id=13396 Signed-off-by: Zhao Yakui <yakui.zhao@intel.com> Acked-by: Zhang Rui <rui.zhang@intel.com> Signed-off-by: Len Brown <len.brown@intel.com>
2009-06-15 20:23:13 -07:00
static inline void acpi_video_unregister(void) { return; }
ACPI: Populate DIDL before registering ACPI video device on Intel Intel graphics hardware that implements the ACPI IGD OpRegion spec requires that the list of display devices be populated before any ACPI video methods are called. Detect when this is the case and defer registration until the opregion code calls it. Fixes crashes on HP laptops. http://bugzilla.kernel.org/show_bug.cgi?id=11259 Signed-off-by: Matthew Garrett <mjg@redhat.com> Acked-by: Eric Anholt <eric@anholt.net> Signed-off-by: Len Brown <len.brown@intel.com>
2009-03-19 14:35:39 -07:00
#endif
#endif
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