drm/i915: don't warn if backlight unexpectedly enabled

commit 813008cd3e93ea8a571b2b7d5b9360a3105b50f7 upstream.

BIOS or firmware can modify hardware state during suspend/resume,
for example on the Toshiba CB35 or Lenovo T400, so log a debug message
instead of a warning if the backlight is unexpectedly enabled.

Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=80930
Cc: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Scot Doyle <lkml14@scotdoyle.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/gpu/drm/i915/intel_panel.c b/drivers/gpu/drm/i915/intel_panel.c
index fd98bec..c6d9777 100644 (file)
--- a/drivers/gpu/drm/i915/intel_panel.c
+++ b/drivers/gpu/drm/i915/intel_panel.c
@@ -645,7 +645,7 @@ static void pch_enable_backlight(struct intel_connector *connector)
 
        cpu_ctl2 = I915_READ(BLC_PWM_CPU_CTL2);
        if (cpu_ctl2 & BLM_PWM_ENABLE) {
-               WARN(1, "cpu backlight already enabled\n");
+               DRM_DEBUG_KMS("cpu backlight already enabled\n");
                cpu_ctl2 &= ~BLM_PWM_ENABLE;
                I915_WRITE(BLC_PWM_CPU_CTL2, cpu_ctl2);
        }
@@ -693,7 +693,7 @@ static void i9xx_enable_backlight(struct intel_connector *connector)
 
        ctl = I915_READ(BLC_PWM_CTL);
        if (ctl & BACKLIGHT_DUTY_CYCLE_MASK_PNV) {
-               WARN(1, "backlight already enabled\n");
+               DRM_DEBUG_KMS("backlight already enabled\n");
                I915_WRITE(BLC_PWM_CTL, 0);
        }
 
@@ -724,7 +724,7 @@ static void i965_enable_backlight(struct intel_connector *connector)
 
        ctl2 = I915_READ(BLC_PWM_CTL2);
        if (ctl2 & BLM_PWM_ENABLE) {
-               WARN(1, "backlight already enabled\n");
+               DRM_DEBUG_KMS("backlight already enabled\n");
                ctl2 &= ~BLM_PWM_ENABLE;
                I915_WRITE(BLC_PWM_CTL2, ctl2);
        }
@@ -758,7 +758,7 @@ static void vlv_enable_backlight(struct intel_connector *connector)
 
        ctl2 = I915_READ(VLV_BLC_PWM_CTL2(pipe));
        if (ctl2 & BLM_PWM_ENABLE) {
-               WARN(1, "backlight already enabled\n");
+               DRM_DEBUG_KMS("backlight already enabled\n");
                ctl2 &= ~BLM_PWM_ENABLE;
                I915_WRITE(VLV_BLC_PWM_CTL2(pipe), ctl2);
        }