gma500: Fix backlight crash

Initial changes to get backlight behaviour we want and to fix backlight crashes
on suspend/resume paths.

[Note: on some boxes this will now produce a warning about the backlight, this
 isn't a regression it's an unfixed but non harmful case I still need to nail]

Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

2 files changed, 34 insertions, 28 deletions

diff --git a/drivers/gpu/drm/gma500/power.c b/drivers/gpu/drm/gma500/power.c
index 972bea7c1af2..94025693bae1 100644
--- a/drivers/gpu/drm/gma500/power.c
+++ b/drivers/gpu/drm/gma500/power.c
@@ -302,7 +302,7 @@ int psb_runtime_suspend(struct device *dev)
 
 int psb_runtime_resume(struct device *dev)
 {
-        return 0;
+        return gma_power_resume(dev);;
 }
 
 int psb_runtime_idle(struct device *dev)
diff --git a/drivers/gpu/drm/gma500/psb_intel_lvds.c b/drivers/gpu/drm/gma500/psb_intel_lvds.c
index 8b951e3afd49..21022e1a977a 100644
--- a/drivers/gpu/drm/gma500/psb_intel_lvds.c
+++ b/drivers/gpu/drm/gma500/psb_intel_lvds.c
@@ -68,20 +68,23 @@ struct psb_intel_lvds_priv {
 static u32 psb_intel_lvds_get_max_backlight(struct drm_device *dev)
 {
         struct drm_psb_private *dev_priv = dev->dev_private;
-        u32 retVal;
+        u32 ret;
 
         if (gma_power_begin(dev, false)) {
-                retVal = ((REG_READ(BLC_PWM_CTL) &
-                          BACKLIGHT_MODULATION_FREQ_MASK) >>
-                          BACKLIGHT_MODULATION_FREQ_SHIFT) * 2;
-
+                ret = REG_READ(BLC_PWM_CTL);
                 gma_power_end(dev);
-        } else
-                retVal = ((dev_priv->saveBLC_PWM_CTL &
-                          BACKLIGHT_MODULATION_FREQ_MASK) >>
-                          BACKLIGHT_MODULATION_FREQ_SHIFT) * 2;
-
-        return retVal;
+        } else /* Powered off, use the saved value */
+                ret = dev_priv->saveBLC_PWM_CTL;
+
+        /* Top 15bits hold the frequency mask */
+        ret = (ret &  BACKLIGHT_MODULATION_FREQ_MASK) >>
+                                        BACKLIGHT_MODULATION_FREQ_SHIFT;
+
+        ret *= 2;       /* Return a 16bit range as needed for setting */
+        if (ret == 0)
+                dev_err(dev->dev, "BL bug: Reg %08x save %08X\n",
+                        REG_READ(BLC_PWM_CTL), dev_priv->saveBLC_PWM_CTL);
+        return ret;
 }
 
 /*
@@ -142,7 +145,7 @@ static int psb_lvds_pwm_set_brightness(struct drm_device *dev, int level)
         max_pwm_blc = psb_intel_lvds_get_max_backlight(dev);
 
         /*BLC_PWM_CTL Should be initiated while backlight device init*/
-        BUG_ON((max_pwm_blc & PSB_BLC_MAX_PWM_REG_FREQ) == 0);
+        BUG_ON(max_pwm_blc == 0);
 
         blc_pwm_duty_cycle = level * max_pwm_blc / BRIGHTNESS_MAX_LEVEL;
 
@@ -154,6 +157,10 @@ static int psb_lvds_pwm_set_brightness(struct drm_device *dev, int level)
                   (max_pwm_blc << PSB_BACKLIGHT_PWM_CTL_SHIFT) |
                   (blc_pwm_duty_cycle));
 
+        dev_info(dev->dev, "Backlight lvds set brightness %08x\n",
+                  (max_pwm_blc << PSB_BACKLIGHT_PWM_CTL_SHIFT) |
+                  (blc_pwm_duty_cycle));
+
         return 0;
 }
 
@@ -162,14 +169,12 @@ static int psb_lvds_pwm_set_brightness(struct drm_device *dev, int level)
  */
 void psb_intel_lvds_set_brightness(struct drm_device *dev, int level)
 {
-        /*u32 blc_pwm_ctl;*/
-        struct drm_psb_private *dev_priv =
-                        (struct drm_psb_private *)dev->dev_private;
+        struct drm_psb_private *dev_priv = dev->dev_private;
 
         dev_dbg(dev->dev, "backlight level is %d\n", level);
 
         if (!dev_priv->lvds_bl) {
-                dev_err(dev->dev, "NO LVDS Backlight Info\n");
+                dev_err(dev->dev, "NO LVDS backlight info\n");
                 return;
         }
 
@@ -190,11 +195,13 @@ static void psb_intel_lvds_set_backlight(struct drm_device *dev, int level)
         u32 blc_pwm_ctl;
 
         if (gma_power_begin(dev, false)) {
-                blc_pwm_ctl =
-                        REG_READ(BLC_PWM_CTL) & ~BACKLIGHT_DUTY_CYCLE_MASK;
+                blc_pwm_ctl = REG_READ(BLC_PWM_CTL);
+                blc_pwm_ctl &= ~BACKLIGHT_DUTY_CYCLE_MASK;
                 REG_WRITE(BLC_PWM_CTL,
                                 (blc_pwm_ctl |
                                 (level << BACKLIGHT_DUTY_CYCLE_SHIFT)));
+                dev_priv->saveBLC_PWM_CTL = (blc_pwm_ctl |
+                                        (level << BACKLIGHT_DUTY_CYCLE_SHIFT));
                 gma_power_end(dev);
         } else {
                 blc_pwm_ctl = dev_priv->saveBLC_PWM_CTL &
@@ -212,9 +219,11 @@ static void psb_intel_lvds_set_power(struct drm_device *dev,
 {
         u32 pp_status;
 
-        if (!gma_power_begin(dev, true))
+        if (!gma_power_begin(dev, true)) {
+                dev_err(dev->dev, "set power, chip off!\n");
                 return;
-
+        }
+        
         if (on) {
                 REG_WRITE(PP_CONTROL, REG_READ(PP_CONTROL) |
                           POWER_TARGET_ON);
@@ -296,9 +305,6 @@ static void psb_intel_lvds_restore(struct drm_connector *connector)
 {
         struct drm_device *dev = connector->dev;
         u32 pp_status;
-
-        /*struct drm_psb_private *dev_priv =
-                                (struct drm_psb_private *)dev->dev_private;*/
         struct psb_intel_output *psb_intel_output =
                                         to_psb_intel_output(connector);
         struct psb_intel_lvds_priv *lvds_priv =
@@ -621,7 +627,8 @@ int psb_intel_lvds_set_property(struct drm_connector *connector,
                         goto set_prop_error;
                 else {
 #ifdef CONFIG_BACKLIGHT_CLASS_DEVICE
-                        struct drm_psb_private *devp = encoder->dev->dev_private;
+                        struct drm_psb_private *devp =
+                                                encoder->dev->dev_private;
                         struct backlight_device *bd = devp->backlight_device;
                         if (bd) {
                                 bd->props.brightness = value;
@@ -694,8 +701,7 @@ void psb_intel_lvds_init(struct drm_device *dev,
         struct drm_encoder *encoder;
         struct drm_display_mode *scan;  /* *modes, *bios_mode; */
         struct drm_crtc *crtc;
-        struct drm_psb_private *dev_priv =
-                                (struct drm_psb_private *)dev->dev_private;
+        struct drm_psb_private *dev_priv = dev->dev_private;
         u32 lvds;
         int pipe;
 
@@ -711,8 +717,8 @@ void psb_intel_lvds_init(struct drm_device *dev,
         }
 
         psb_intel_output->dev_priv = lvds_priv;
-
         psb_intel_output->mode_dev = mode_dev;
+
         connector = &psb_intel_output->base;
         encoder = &psb_intel_output->enc;
         drm_connector_init(dev, &psb_intel_output->base,