drm/i915: Acer C720 and C720P have controllable backlights

commit 2e93a1aa9ca455aa3ad0294bcd6d66f38bf8b758 upstream.

The Acer C720 and C720P Chromebooks (with Celeron 2955U CPU) have a
controllable backlight although their VBT reports otherwise. Apply quirk
to ignore the backlight presence check during backlight setup.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=79813
Tested-by: James Duley <jagduley@gmail.com>
Tested-by: Michael Mullin <masmullin@gmail.com>
Signed-off-by: Scot Doyle <lkml14@scotdoyle.com>
CC: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
[danvet: Add cc: stable because the regressing commit is in 3.15.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 7d7d98c70ef661001c64998d43cae473ad1491ed..3c58d0972e9d26507604fb6b038844bf9f3499bd 100644 (file)
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -11245,6 +11245,9 @@ static struct intel_quirk intel_quirks[] = {
 
        /* Acer Aspire 5336 */
        { 0x2a42, 0x1025, 0x048a, quirk_invert_brightness },
+
+       /* Acer C720 and C720P Chromebooks (Celeron 2955U) have backlights */
+       { 0x0a06, 0x1025, 0x0a11, quirk_backlight_present },
 };
 
 static void intel_init_quirks(struct drm_device *dev)