drm/i915: Refactor panel backlight controls

There were two instances of code to control the panel backlight and
neither handled the complete set of device variations.

Fixes:

  Bug 29716 - [GM965] Regression: Backlight resets to minimum when changing resolution
  https://bugs.freedesktop.org/show_bug.cgi?id=29716

And a bug on one of my PineView boxes which overflowed the backlight
value.

Incorporates part of a similar patch by Matthew Garrett that exposes a
native Intel backlight controller.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index e6fbeb4..cfc8bfd 100644 (file)
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -319,7 +319,7 @@ typedef struct drm_i915_private {
        struct intel_overlay *overlay;
 
        /* LVDS info */
-       int backlight_duty_cycle;  /* restore backlight to this value */
+       int backlight_level;  /* restore backlight to this value */
        bool panel_wants_dither;
        struct drm_display_mode *panel_fixed_mode;
        struct drm_display_mode *lfp_lvds_vbt_mode; /* if any */

diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index 949cfda..cdf9c78 100644 (file)
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -204,13 +204,16 @@ extern bool intel_pch_has_edp(struct drm_crtc *crtc);
 extern bool intel_dpd_is_edp(struct drm_device *dev);
 extern void intel_edp_link_config (struct intel_encoder *, int *, int *);
 
-
+/* intel_panel.c */
 extern void intel_fixed_panel_mode(struct drm_display_mode *fixed_mode,
                                   struct drm_display_mode *adjusted_mode);
 extern void intel_pch_panel_fitting(struct drm_device *dev,
                                    int fitting_mode,
                                    struct drm_display_mode *mode,
                                    struct drm_display_mode *adjusted_mode);
+extern u32 intel_panel_get_max_backlight(struct drm_device *dev);
+extern u32 intel_panel_get_backlight(struct drm_device *dev);
+extern void intel_panel_set_backlight(struct drm_device *dev, u32 level);
 
 extern int intel_panel_fitter_pipe (struct drm_device *dev);
 extern void intel_crtc_load_lut(struct drm_crtc *crtc);

diff --git a/drivers/gpu/drm/i915/intel_lvds.c b/drivers/gpu/drm/i915/intel_lvds.c
index 047bd95..8320279 100644 (file)
--- a/drivers/gpu/drm/i915/intel_lvds.c
+++ b/drivers/gpu/drm/i915/intel_lvds.c
@@ -53,43 +53,6 @@ static struct intel_lvds *enc_to_intel_lvds(struct drm_encoder *encoder)
        return container_of(enc_to_intel_encoder(encoder), struct intel_lvds, base);
 }
 
-/**
- * Sets the backlight level.
- *
- * \param level backlight level, from 0 to intel_lvds_get_max_backlight().
- */
-static void intel_lvds_set_backlight(struct drm_device *dev, int level)
-{
-       struct drm_i915_private *dev_priv = dev->dev_private;
-       u32 blc_pwm_ctl, reg;
-
-       if (HAS_PCH_SPLIT(dev))
-               reg = BLC_PWM_CPU_CTL;
-       else
-               reg = BLC_PWM_CTL;
-
-       blc_pwm_ctl = I915_READ(reg) & ~BACKLIGHT_DUTY_CYCLE_MASK;
-       I915_WRITE(reg, (blc_pwm_ctl |
-                                (level << BACKLIGHT_DUTY_CYCLE_SHIFT)));
-}
-
-/**
- * Returns the maximum level of the backlight duty cycle field.
- */
-static u32 intel_lvds_get_max_backlight(struct drm_device *dev)
-{
-       struct drm_i915_private *dev_priv = dev->dev_private;
-       u32 reg;
-
-       if (HAS_PCH_SPLIT(dev))
-               reg = BLC_PWM_PCH_CTL2;
-       else
-               reg = BLC_PWM_CTL;
-
-       return ((I915_READ(reg) & BACKLIGHT_MODULATION_FREQ_MASK) >>
-               BACKLIGHT_MODULATION_FREQ_SHIFT) * 2;
-}
-
 /**
  * Sets the power state for the panel.
  */
@@ -117,9 +80,9 @@ static void intel_lvds_set_power(struct drm_device *dev, bool on)
                if (wait_for(I915_READ(status_reg) & PP_ON, 1000))
                        DRM_ERROR("timed out waiting to enable LVDS pipe");
 
-               intel_lvds_set_backlight(dev, dev_priv->backlight_duty_cycle);
+               intel_panel_set_backlight(dev, dev_priv->backlight_level);
        } else {
-               intel_lvds_set_backlight(dev, 0);
+               intel_panel_set_backlight(dev, 0);
 
                I915_WRITE(ctl_reg, I915_READ(ctl_reg) &
                           ~POWER_TARGET_ON);
@@ -386,16 +349,8 @@ static void intel_lvds_prepare(struct drm_encoder *encoder)
 {
        struct drm_device *dev = encoder->dev;
        struct drm_i915_private *dev_priv = dev->dev_private;
-       u32 reg;
-
-       if (HAS_PCH_SPLIT(dev))
-               reg = BLC_PWM_CPU_CTL;
-       else
-               reg = BLC_PWM_CTL;
 
-       dev_priv->saveBLC_PWM_CTL = I915_READ(reg);
-       dev_priv->backlight_duty_cycle = (dev_priv->saveBLC_PWM_CTL &
-                                      BACKLIGHT_DUTY_CYCLE_MASK);
+       dev_priv->backlight_level = intel_panel_get_backlight(dev);
 
        intel_lvds_set_power(dev, false);
 }
@@ -405,9 +360,8 @@ static void intel_lvds_commit( struct drm_encoder *encoder)
        struct drm_device *dev = encoder->dev;
        struct drm_i915_private *dev_priv = dev->dev_private;
 
-       if (dev_priv->backlight_duty_cycle == 0)
-               dev_priv->backlight_duty_cycle =
-                       intel_lvds_get_max_backlight(dev);
+       if (dev_priv->backlight_level == 0)
+               dev_priv->backlight_level = intel_panel_get_max_backlight(dev);
 
        intel_lvds_set_power(dev, true);
 }

diff --git a/drivers/gpu/drm/i915/intel_opregion.c b/drivers/gpu/drm/i915/intel_opregion.c
index 3cb1323..917c7dc 100644 (file)
--- a/drivers/gpu/drm/i915/intel_opregion.c
+++ b/drivers/gpu/drm/i915/intel_opregion.c
@@ -31,9 +31,9 @@
 #include "drmP.h"
 #include "i915_drm.h"
 #include "i915_drv.h"
+#include "intel_drv.h"
 
 #define PCI_ASLE 0xe4
-#define PCI_LBPC 0xf4
 #define PCI_ASLS 0xfc
 
 #define OPREGION_HEADER_OFFSET 0
@@ -147,36 +147,17 @@ static u32 asle_set_backlight(struct drm_device *dev, u32 bclp)
 {
        struct drm_i915_private *dev_priv = dev->dev_private;
        struct opregion_asle *asle = dev_priv->opregion.asle;
-       u32 blc_pwm_ctl, blc_pwm_ctl2;
-       u32 max_backlight, level, shift;
+       u32 max;
 
        if (!(bclp & ASLE_BCLP_VALID))
                return ASLE_BACKLIGHT_FAILED;
 
        bclp &= ASLE_BCLP_MSK;
-       if (bclp < 0 || bclp > 255)
+       if (bclp > 255)
                return ASLE_BACKLIGHT_FAILED;
 
-       blc_pwm_ctl = I915_READ(BLC_PWM_CTL);
-       blc_pwm_ctl2 = I915_READ(BLC_PWM_CTL2);
-
-       if (IS_I965G(dev) && (blc_pwm_ctl2 & BLM_COMBINATION_MODE))
-               pci_write_config_dword(dev->pdev, PCI_LBPC, bclp);
-       else {
-               if (IS_PINEVIEW(dev)) {
-                       blc_pwm_ctl &= ~(BACKLIGHT_DUTY_CYCLE_MASK - 1);
-                       max_backlight = (blc_pwm_ctl & BACKLIGHT_MODULATION_FREQ_MASK) >> 
-                                       BACKLIGHT_MODULATION_FREQ_SHIFT;
-                       shift = BACKLIGHT_DUTY_CYCLE_SHIFT + 1;
-               } else {
-                       blc_pwm_ctl &= ~BACKLIGHT_DUTY_CYCLE_MASK;
-                       max_backlight = ((blc_pwm_ctl & BACKLIGHT_MODULATION_FREQ_MASK) >> 
-                                       BACKLIGHT_MODULATION_FREQ_SHIFT) * 2;
-                       shift = BACKLIGHT_DUTY_CYCLE_SHIFT;
-               }
-               level = (bclp * max_backlight) / 255;
-               I915_WRITE(BLC_PWM_CTL, blc_pwm_ctl | (level << shift));
-       }
+       max = intel_panel_get_max_backlight(dev);
+       intel_panel_set_backlight(dev, bclp * max / 255);
        asle->cblv = (bclp*0x64)/0xff | ASLE_CBLV_VALID;
 
        return 0;
@@ -243,36 +224,6 @@ void intel_opregion_asle_intr(struct drm_device *dev)
        asle->aslc = asle_stat;
 }
 
-static u32 asle_set_backlight_ironlake(struct drm_device *dev, u32 bclp)
-{
-       struct drm_i915_private *dev_priv = dev->dev_private;
-       struct opregion_asle *asle = dev_priv->opregion.asle;
-       u32 cpu_pwm_ctl, pch_pwm_ctl2;
-       u32 max_backlight, level;
-
-       if (!(bclp & ASLE_BCLP_VALID))
-               return ASLE_BACKLIGHT_FAILED;
-
-       bclp &= ASLE_BCLP_MSK;
-       if (bclp < 0 || bclp > 255)
-               return ASLE_BACKLIGHT_FAILED;
-
-       cpu_pwm_ctl = I915_READ(BLC_PWM_CPU_CTL);
-       pch_pwm_ctl2 = I915_READ(BLC_PWM_PCH_CTL2);
-       /* get the max PWM frequency */
-       max_backlight = (pch_pwm_ctl2 >> 16) & BACKLIGHT_DUTY_CYCLE_MASK;
-       /* calculate the expected PMW frequency */
-       level = (bclp * max_backlight) / 255;
-       /* reserve the high 16 bits */
-       cpu_pwm_ctl &= ~(BACKLIGHT_DUTY_CYCLE_MASK);
-       /* write the updated PWM frequency */
-       I915_WRITE(BLC_PWM_CPU_CTL, cpu_pwm_ctl | level);
-
-       asle->cblv = (bclp*0x64)/0xff | ASLE_CBLV_VALID;
-
-       return 0;
-}
-
 /* Only present on Ironlake+ */
 void intel_opregion_gse_intr(struct drm_device *dev)
 {
@@ -297,7 +248,7 @@ void intel_opregion_gse_intr(struct drm_device *dev)
        }
 
        if (asle_req & ASLE_SET_BACKLIGHT)
-               asle_stat |= asle_set_backlight_ironlake(dev, asle->bclp);
+               asle_stat |= asle_set_backlight(dev, asle->bclp);
 
        if (asle_req & ASLE_SET_PFIT) {
                DRM_DEBUG_DRIVER("Pfit is not supported\n");

diff --git a/drivers/gpu/drm/i915/intel_panel.c b/drivers/gpu/drm/i915/intel_panel.c
index e7f5299..30abe7a 100644 (file)
--- a/drivers/gpu/drm/i915/intel_panel.c
+++ b/drivers/gpu/drm/i915/intel_panel.c
@@ -30,6 +30,8 @@
 
 #include "intel_drv.h"
 
+#define PCI_LBPC 0xf4 /* legacy/combination backlight modes */
+
 void
 intel_fixed_panel_mode(struct drm_display_mode *fixed_mode,
                       struct drm_display_mode *adjusted_mode)
@@ -109,3 +111,110 @@ done:
        dev_priv->pch_pf_pos = (x << 16) | y;
        dev_priv->pch_pf_size = (width << 16) | height;
 }
+
+static int is_backlight_combination_mode(struct drm_device *dev)
+{
+       struct drm_i915_private *dev_priv = dev->dev_private;
+
+       if (IS_I965G(dev))
+               return I915_READ(BLC_PWM_CTL2) & BLM_COMBINATION_MODE;
+
+       if (IS_GEN2(dev))
+               return I915_READ(BLC_PWM_CTL) & BLM_LEGACY_MODE;
+
+       return 0;
+}
+
+u32 intel_panel_get_max_backlight(struct drm_device *dev)
+{
+       struct drm_i915_private *dev_priv = dev->dev_private;
+       u32 max;
+
+       if (HAS_PCH_SPLIT(dev)) {
+               max = I915_READ(BLC_PWM_PCH_CTL2) >> 16;
+       } else {
+               max = I915_READ(BLC_PWM_CTL);
+               if (IS_PINEVIEW(dev)) {
+                       max >>= 17;
+               } else {
+                       max >>= 16;
+                       if (!IS_I965G(dev))
+                               max &= ~1;
+               }
+
+               if (is_backlight_combination_mode(dev))
+                       max *= 0xff;
+       }
+
+       if (max == 0) {
+               /* XXX add code here to query mode clock or hardware clock
+                * and program max PWM appropriately.
+                */
+               DRM_ERROR("fixme: max PWM is zero.\n");
+               max = 1;
+       }
+
+       DRM_DEBUG_DRIVER("max backlight PWM = %d\n", max);
+       return max;
+}
+
+u32 intel_panel_get_backlight(struct drm_device *dev)
+{
+       struct drm_i915_private *dev_priv = dev->dev_private;
+       u32 val;
+
+       if (HAS_PCH_SPLIT(dev)) {
+               val = I915_READ(BLC_PWM_CPU_CTL) & BACKLIGHT_DUTY_CYCLE_MASK;
+       } else {
+               val = I915_READ(BLC_PWM_CTL) & BACKLIGHT_DUTY_CYCLE_MASK;
+               if (IS_PINEVIEW(dev))
+                       val >>= 1;
+
+               if (is_backlight_combination_mode(dev)){
+                       u8 lbpc;
+
+                       val &= ~1;
+                       pci_read_config_byte(dev->pdev, PCI_LBPC, &lbpc);
+                       val *= lbpc;
+                       val >>= 1;
+               }
+       }
+
+       DRM_DEBUG_DRIVER("get backlight PWM = %d\n", val);
+       return val;
+}
+
+static void intel_pch_panel_set_backlight(struct drm_device *dev, u32 level)
+{
+       struct drm_i915_private *dev_priv = dev->dev_private;
+       u32 val = I915_READ(BLC_PWM_CPU_CTL) & ~BACKLIGHT_DUTY_CYCLE_MASK;
+       I915_WRITE(BLC_PWM_CPU_CTL, val | level);
+}
+
+void intel_panel_set_backlight(struct drm_device *dev, u32 level)
+{
+       struct drm_i915_private *dev_priv = dev->dev_private;
+       u32 tmp;
+
+       DRM_DEBUG_DRIVER("set backlight PWM = %d\n", level);
+
+       if (HAS_PCH_SPLIT(dev))
+               return intel_pch_panel_set_backlight(dev, level);
+
+       if (is_backlight_combination_mode(dev)){
+               u32 max = intel_panel_get_max_backlight(dev);
+               u8 lpbc;
+
+               lpbc = level * 0xfe / max + 1;
+               level /= lpbc;
+               pci_write_config_byte(dev->pdev, PCI_LBPC, lpbc);
+       }
+
+       tmp = I915_READ(BLC_PWM_CTL);
+       if (IS_PINEVIEW(dev)) {
+               tmp &= ~(BACKLIGHT_DUTY_CYCLE_MASK - 1);
+               level <<= 1;
+       } else
+               tmp &= ~BACKLIGHT_DUTY_CYCLE_MASK;
+       I915_WRITE(BLC_PWM_CTL, tmp | level);
+}