drm/i915/lvds: Connect the PWM to the LVDS pipe
... and do not just assume to always use pipe B.
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
diff --git a/drivers/gpu/drm/i915/intel_lvds.c b/drivers/gpu/drm/i915/intel_lvds.c
index 23247b2..d07055c 100644
--- a/drivers/gpu/drm/i915/intel_lvds.c
+++ b/drivers/gpu/drm/i915/intel_lvds.c
@@ -1012,10 +1012,18 @@
out:
if (HAS_PCH_SPLIT(dev)) {
u32 pwm;
- /* make sure PWM is enabled */
+
+ pipe = (I915_READ(PCH_LVDS) & LVDS_PIPEB_SELECT) ? 1 : 0;
+
+ /* make sure PWM is enabled and locked to the LVDS pipe */
pwm = I915_READ(BLC_PWM_CPU_CTL2);
- pwm |= (PWM_ENABLE | PWM_PIPE_B);
- I915_WRITE(BLC_PWM_CPU_CTL2, pwm);
+ if (pipe == 0 && (pwm & PWM_PIPE_B))
+ I915_WRITE(BLC_PWM_CPU_CTL2, pwm & ~PWM_ENABLE);
+ if (pipe)
+ pwm |= PWM_PIPE_B;
+ else
+ pwm &= ~PWM_PIPE_B;
+ I915_WRITE(BLC_PWM_CPU_CTL2, pwm | PWM_ENABLE);
pwm = I915_READ(BLC_PWM_PCH_CTL1);
pwm |= PWM_PCH_ENABLE;