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path: root/drivers/gpu/drm/i915/intel_panel.c
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Diffstat (limited to 'drivers/gpu/drm/i915/intel_panel.c')
-rw-r--r--drivers/gpu/drm/i915/intel_panel.c14
1 files changed, 14 insertions, 0 deletions
diff --git a/drivers/gpu/drm/i915/intel_panel.c b/drivers/gpu/drm/i915/intel_panel.c
index b05c6d9b3be7..a24df35e11e7 100644
--- a/drivers/gpu/drm/i915/intel_panel.c
+++ b/drivers/gpu/drm/i915/intel_panel.c
@@ -732,6 +732,20 @@ static void lpt_disable_backlight(struct intel_connector *connector)
intel_panel_actually_set_backlight(connector, 0);
+ /*
+ * Although we don't support or enable CPU PWM with LPT/SPT based
+ * systems, it may have been enabled prior to loading the
+ * driver. Disable to avoid warnings on LCPLL disable.
+ *
+ * This needs rework if we need to add support for CPU PWM on PCH split
+ * platforms.
+ */
+ tmp = I915_READ(BLC_PWM_CPU_CTL2);
+ if (tmp & BLM_PWM_ENABLE) {
+ DRM_DEBUG_KMS("cpu backlight was enabled, disabling\n");
+ I915_WRITE(BLC_PWM_CPU_CTL2, tmp & ~BLM_PWM_ENABLE);
+ }
+
tmp = I915_READ(BLC_PWM_PCH_CTL1);
I915_WRITE(BLC_PWM_PCH_CTL1, tmp & ~BLM_PCH_PWM_ENABLE);
}