drm/i915/vlv: hack to init backlight regs if BIOS fails to do so v2
authorJesse Barnes <jbarnes@virtuousgeek.org>
Wed, 25 Sep 2013 21:04:32 +0000 (14:04 -0700)
committerDaniel Vetter <daniel.vetter@ffwll.ch>
Tue, 1 Oct 2013 05:45:41 +0000 (07:45 +0200)
commitafc85b9d9e617e602006d8766d04e0b8ac9c1b74
tree1cc35f1e87f2a357214808c4c85ff2fa8f21d26a
parent573e74adbd13dff6a5d88aff4d7b19410fc2cb9a
drm/i915/vlv: hack to init backlight regs if BIOS fails to do so v2

Still digging up the actual VBT info for this, but wanted to get this
out there for testing, or in case others are also bugged by this.

This can happen if you boot with an external display connected.  In that
case, the attached eDP backlight modulation frequency may not be
programmed, so we need to use something (in this case the value my BIOS
normally programs with just the internal display enabled).

v2: fix masking and magic value in read_blc_pwm_ctl (Jani)

Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=67732
Tested-by: shui yangwei <yangweix.shui@intel.com> (v1)
Reviewed-by: Jani Nikula <jani.nikula@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
drivers/gpu/drm/i915/intel_panel.c