BLC_PWM_CTL2 is for 965+ only, so add device model check for
legacy backlight control.

For native backlight control, it maps the backlight value (0~255)
in opregion ASLE[BCLP] to backlight duty cycle (0~max_backlight)
and set into control register.

It also add support for IGD device, which follows opregion spec.
Signed-off-by: NLi Peng <peng.li@intel.com>
Signed-off-by: NJesse Barnes <jbarnes@virtuousgeek.org>

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=13396Signed-off-by: NZhao Yakui <yakui.zhao@intel.com>
Acked-by: NZhang Rui <rui.zhang@intel.com>
Signed-off-by: NLen Brown <len.brown@intel.com>

The ACPI video driver defers registration to the i915 driver if the
system supports opregion-mediated backlight control. This registration
was only being performed in the KMS case. Ensure it's done even if we
don't have modesetting enabled.

http://bugzilla.kernel.org/show_bug.cgi?id=13048Signed-off-by: NMatthew Garrett <mjg@redhat.com>
Signed-off-by: NLen Brown <len.brown@intel.com>

The changes to opregion initialisation order meant that the ASLE setup
code might not be run at the correct time. Ensure that the interrupts are
set up.
Signed-off-by: NMatthew Garrett <mjg@redhat.com>
Signed-off-by: NEric Anholt <eric@anholt.net>

The i915 DRM triggers registration of the ACPI video driver on load. It
should unregister it at unload in order to avoid generating backtraces on
being reloaded.
Signed-off-by: NMatthew Garrett <mjg@redhat.com>
Signed-off-by: NEric Anholt <eric@anholt.net>

The ACPI video driver defers registration to the i915 driver if the
system supports opregion-mediated backlight control. This registration
was only being performed in the KMS case. Ensure it's done even if we
don't have modesetting enabled.
Signed-off-by: NMatthew Garrett <mjg@redhat.com>
Signed-off-by: NEric Anholt <eric@anholt.net>

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=11259Signed-off-by: NMatthew Garrett <mjg@redhat.com>
Acked-by: NEric Anholt <eric@anholt.net>
Signed-off-by: NLen Brown <len.brown@intel.com>

Signed-off-by: NHannes Eder <hannes@hanneseder.net>
Signed-off-by: NEric Anholt <eric@anholt.net>
Signed-off-by: NDave Airlie <airlied@linux.ie>

The pipestat fields affect reporting of all vblank-related interrupts, so we
have to reset them during the irq_handler, and while enabling vblank
interrupts.  Otherwise, if a pipe status field had been set to non-zero
before enabling reporting, we would never see an interrupt again.

This patch adds i915_enable_pipestat and i915_disable_pipestat to abstract
out the steps needed to change the reported interrupts.
Signed-off-by: NKeith Packard <keithp@keithp.com>
Signed-off-by: NEric Anholt <eric@anholt.net>
Signed-off-by: NDave Airlie <airlied@redhat.com>

This adds the support necessary for allowing ACPI backlight control to
work on some newer Intel-based graphics systems. Tested on Thinkpad T61
and HP 2510p hardware.
Signed-off-by: NMatthew Garrett <mjg@redhat.com>
Signed-off-by: NDave Airlie <airlied@linux.ie>