diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 1a12d44b9710..04439e888380 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -2972,6 +2972,13 @@ enum skl_disp_power_wells {
 #define OGAMC1			_MMIO(0x30020)
 #define OGAMC0			_MMIO(0x30024)
 
+/*
+ * GEN9 clock gating regs
+ */
+#define GEN9_CLKGATE_DIS_0		_MMIO(0x46530)
+#define   PWM2_GATING_DIS		(1 << 14)
+#define   PWM1_GATING_DIS		(1 << 13)
+
 /*
  * Display engine regs
  */
diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index 96f45d7b3e4b..612a8b462294 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -66,6 +66,14 @@ static void bxt_init_clock_gating(struct drm_device *dev)
 	 */
 	I915_WRITE(GEN8_UCGCTL6, I915_READ(GEN8_UCGCTL6) |
 		   GEN8_HDCUNIT_CLOCK_GATE_DISABLE_HDCREQ);
+
+	/*
+	 * Wa: Backlight PWM may stop in the asserted state, causing backlight
+	 * to stay fully on.
+	 */
+	if (IS_BXT_REVID(dev_priv, BXT_REVID_B0, REVID_FOREVER))
+		I915_WRITE(GEN9_CLKGATE_DIS_0, I915_READ(GEN9_CLKGATE_DIS_0) |
+			   PWM1_GATING_DIS | PWM2_GATING_DIS);
 }
 
 static void i915_pineview_get_mem_freq(struct drm_device *dev)