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authorMatthew Garrett <mjg59@srcf.ucam.org>2008-08-05 19:37:25 +0100
committerDave Airlie <airlied@linux.ie>2008-10-18 07:10:10 +1000
commit8ee1c3db9075cb3211352e737e0feb98fd733b20 (patch)
treead91cc8b4ce57fdfdbac8920ba4b352a6871c782 /drivers/gpu
parent398c9cb20b5c6c5d1313912b937d653a46fec578 (diff)
Add Intel ACPI IGD OpRegion support
This adds the support necessary for allowing ACPI backlight control to work on some newer Intel-based graphics systems. Tested on Thinkpad T61 and HP 2510p hardware. Signed-off-by: Matthew Garrett <mjg@redhat.com> Signed-off-by: Dave Airlie <airlied@linux.ie>
Diffstat (limited to 'drivers/gpu')
-rw-r--r--drivers/gpu/drm/i915/Makefile2
-rw-r--r--drivers/gpu/drm/i915/i915_dma.c4
-rw-r--r--drivers/gpu/drm/i915/i915_drv.c4
-rw-r--r--drivers/gpu/drm/i915/i915_drv.h17
-rw-r--r--drivers/gpu/drm/i915/i915_irq.c25
-rw-r--r--drivers/gpu/drm/i915/i915_opregion.c371
-rw-r--r--drivers/gpu/drm/i915/i915_reg.h1
7 files changed, 415 insertions, 9 deletions
diff --git a/drivers/gpu/drm/i915/Makefile b/drivers/gpu/drm/i915/Makefile
index a9e60464df7..b032808d9c1 100644
--- a/drivers/gpu/drm/i915/Makefile
+++ b/drivers/gpu/drm/i915/Makefile
@@ -3,7 +3,7 @@
# Direct Rendering Infrastructure (DRI) in XFree86 4.1.0 and higher.
ccflags-y := -Iinclude/drm
-i915-y := i915_drv.o i915_dma.o i915_irq.o i915_mem.o
+i915-y := i915_drv.o i915_dma.o i915_irq.o i915_mem.o i915_opregion.o
i915-$(CONFIG_COMPAT) += i915_ioc32.o
diff --git a/drivers/gpu/drm/i915/i915_dma.c b/drivers/gpu/drm/i915/i915_dma.c
index f1b5aa92fa8..29115450ee4 100644
--- a/drivers/gpu/drm/i915/i915_dma.c
+++ b/drivers/gpu/drm/i915/i915_dma.c
@@ -810,6 +810,8 @@ int i915_driver_load(struct drm_device *dev, unsigned long flags)
if (!IS_I945G(dev) && !IS_I945GM(dev))
pci_enable_msi(dev->pdev);
+ intel_opregion_init(dev);
+
spin_lock_init(&dev_priv->user_irq_lock);
return ret;
@@ -827,6 +829,8 @@ int i915_driver_unload(struct drm_device *dev)
if (dev_priv->mmio_map)
drm_rmmap(dev, dev_priv->mmio_map);
+ intel_opregion_free(dev);
+
drm_free(dev->dev_private, sizeof(drm_i915_private_t),
DRM_MEM_DRIVER);
diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
index 6c99aab12da..d95eca2bc45 100644
--- a/drivers/gpu/drm/i915/i915_drv.c
+++ b/drivers/gpu/drm/i915/i915_drv.c
@@ -371,6 +371,8 @@ static int i915_suspend(struct drm_device *dev, pm_message_t state)
i915_save_vga(dev);
+ intel_opregion_free(dev);
+
if (state.event == PM_EVENT_SUSPEND) {
/* Shut down the device */
pci_disable_device(dev->pdev);
@@ -532,6 +534,8 @@ static int i915_resume(struct drm_device *dev)
i915_restore_vga(dev);
+ intel_opregion_init(dev);
+
return 0;
}
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 8daf0d84cd5..e4bd01c511a 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -82,6 +82,14 @@ typedef struct _drm_i915_vbl_swap {
unsigned int sequence;
} drm_i915_vbl_swap_t;
+struct intel_opregion {
+ struct opregion_header *header;
+ struct opregion_acpi *acpi;
+ struct opregion_swsci *swsci;
+ struct opregion_asle *asle;
+ int enabled;
+};
+
typedef struct drm_i915_private {
drm_local_map_t *sarea;
drm_local_map_t *mmio_map;
@@ -122,6 +130,8 @@ typedef struct drm_i915_private {
drm_i915_vbl_swap_t vbl_swaps;
unsigned int swaps_pending;
+ struct intel_opregion opregion;
+
/* Register state */
u8 saveLBB;
u32 saveDSPACNTR;
@@ -244,6 +254,7 @@ extern int i915_vblank_pipe_get(struct drm_device *dev, void *data,
struct drm_file *file_priv);
extern int i915_vblank_swap(struct drm_device *dev, void *data,
struct drm_file *file_priv);
+extern void i915_enable_irq(drm_i915_private_t *dev_priv, u32 mask);
/* i915_mem.c */
extern int i915_mem_alloc(struct drm_device *dev, void *data,
@@ -258,6 +269,12 @@ extern void i915_mem_takedown(struct mem_block **heap);
extern void i915_mem_release(struct drm_device * dev,
struct drm_file *file_priv, struct mem_block *heap);
+/* i915_opregion.c */
+extern int intel_opregion_init(struct drm_device *dev);
+extern void intel_opregion_free(struct drm_device *dev);
+extern void opregion_asle_intr(struct drm_device *dev);
+extern void opregion_enable_asle(struct drm_device *dev);
+
#define I915_READ(reg) DRM_READ32(dev_priv->mmio_map, (reg))
#define I915_WRITE(reg,val) DRM_WRITE32(dev_priv->mmio_map, (reg), (val))
#define I915_READ16(reg) DRM_READ16(dev_priv->mmio_map, (reg))
diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index 24d11ed5bbc..ae7d3a82a6d 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -36,9 +36,11 @@
/** These are the interrupts used by the driver */
#define I915_INTERRUPT_ENABLE_MASK (I915_USER_INTERRUPT | \
I915_DISPLAY_PIPE_A_VBLANK_INTERRUPT | \
- I915_DISPLAY_PIPE_B_VBLANK_INTERRUPT)
+ I915_DISPLAY_PIPE_B_VBLANK_INTERRUPT | \
+ I915_ASLE_INTERRUPT | \
+ I915_DISPLAY_PIPE_B_EVENT_INTERRUPT)
-static inline void
+void
i915_enable_irq(drm_i915_private_t *dev_priv, u32 mask)
{
if ((dev_priv->irq_mask_reg & mask) != 0) {
@@ -274,6 +276,9 @@ irqreturn_t i915_driver_irq_handler(DRM_IRQ_ARGS)
return IRQ_NONE;
}
+ I915_WRITE(PIPEASTAT, pipea_stats);
+ I915_WRITE(PIPEBSTAT, pipeb_stats);
+
I915_WRITE(IIR, iir);
if (dev->pdev->msi_enabled)
I915_WRITE(IMR, dev_priv->irq_mask_reg);
@@ -306,14 +311,14 @@ irqreturn_t i915_driver_irq_handler(DRM_IRQ_ARGS)
if (dev_priv->swaps_pending > 0)
drm_locked_tasklet(dev, i915_vblank_tasklet);
- I915_WRITE(PIPEASTAT,
- pipea_stats|I915_VBLANK_INTERRUPT_ENABLE|
- PIPE_VBLANK_INTERRUPT_STATUS);
- I915_WRITE(PIPEBSTAT,
- pipeb_stats|I915_VBLANK_INTERRUPT_ENABLE|
- PIPE_VBLANK_INTERRUPT_STATUS);
}
+ if (iir & I915_ASLE_INTERRUPT)
+ opregion_asle_intr(dev);
+
+ if (iir & I915_DISPLAY_PIPE_B_EVENT_INTERRUPT)
+ opregion_asle_intr(dev);
+
return IRQ_HANDLED;
}
@@ -661,10 +666,14 @@ void i915_driver_irq_postinstall(struct drm_device * dev)
if (dev_priv->vblank_pipe & DRM_I915_VBLANK_PIPE_B)
dev_priv->irq_mask_reg &= ~I915_DISPLAY_PIPE_B_VBLANK_INTERRUPT;
+ dev_priv->irq_mask_reg &= I915_INTERRUPT_ENABLE_MASK;
+
I915_WRITE(IMR, dev_priv->irq_mask_reg);
I915_WRITE(IER, I915_INTERRUPT_ENABLE_MASK);
(void) I915_READ(IER);
+ opregion_enable_asle(dev);
+
DRM_INIT_WAITQUEUE(&dev_priv->irq_queue);
}
diff --git a/drivers/gpu/drm/i915/i915_opregion.c b/drivers/gpu/drm/i915/i915_opregion.c
new file mode 100644
index 00000000000..1787a0c7e3a
--- /dev/null
+++ b/drivers/gpu/drm/i915/i915_opregion.c
@@ -0,0 +1,371 @@
+/*
+ * Copyright 2008 Intel Corporation <hong.liu@intel.com>
+ * Copyright 2008 Red Hat <mjg@redhat.com>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining
+ * a copy of this software and associated documentation files (the
+ * "Software"), to deal in the Software without restriction, including
+ * without limitation the rights to use, copy, modify, merge, publish,
+ * distribute, sub license, and/or sell copies of the Software, and to
+ * permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the
+ * next paragraph) shall be included in all copies or substantial
+ * portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+ * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+ * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+ * NON-INFRINGEMENT. IN NO EVENT SHALL INTEL AND/OR ITS SUPPLIERS BE
+ * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
+ * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
+ * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+ * SOFTWARE.
+ *
+ */
+
+#include <linux/acpi.h>
+
+#include "drmP.h"
+#include "i915_drm.h"
+#include "i915_drv.h"
+
+#define PCI_ASLE 0xe4
+#define PCI_LBPC 0xf4
+#define PCI_ASLS 0xfc
+
+#define OPREGION_SZ (8*1024)
+#define OPREGION_HEADER_OFFSET 0
+#define OPREGION_ACPI_OFFSET 0x100
+#define OPREGION_SWSCI_OFFSET 0x200
+#define OPREGION_ASLE_OFFSET 0x300
+#define OPREGION_VBT_OFFSET 0x1000
+
+#define OPREGION_SIGNATURE "IntelGraphicsMem"
+#define MBOX_ACPI (1<<0)
+#define MBOX_SWSCI (1<<1)
+#define MBOX_ASLE (1<<2)
+
+struct opregion_header {
+ u8 signature[16];
+ u32 size;
+ u32 opregion_ver;
+ u8 bios_ver[32];
+ u8 vbios_ver[16];
+ u8 driver_ver[16];
+ u32 mboxes;
+ u8 reserved[164];
+} __attribute__((packed));
+
+/* OpRegion mailbox #1: public ACPI methods */
+struct opregion_acpi {
+ u32 drdy; /* driver readiness */
+ u32 csts; /* notification status */
+ u32 cevt; /* current event */
+ u8 rsvd1[20];
+ u32 didl[8]; /* supported display devices ID list */
+ u32 cpdl[8]; /* currently presented display list */
+ u32 cadl[8]; /* currently active display list */
+ u32 nadl[8]; /* next active devices list */
+ u32 aslp; /* ASL sleep time-out */
+ u32 tidx; /* toggle table index */
+ u32 chpd; /* current hotplug enable indicator */
+ u32 clid; /* current lid state*/
+ u32 cdck; /* current docking state */
+ u32 sxsw; /* Sx state resume */
+ u32 evts; /* ASL supported events */
+ u32 cnot; /* current OS notification */
+ u32 nrdy; /* driver status */
+ u8 rsvd2[60];
+} __attribute__((packed));
+
+/* OpRegion mailbox #2: SWSCI */
+struct opregion_swsci {
+ u32 scic; /* SWSCI command|status|data */
+ u32 parm; /* command parameters */
+ u32 dslp; /* driver sleep time-out */
+ u8 rsvd[244];
+} __attribute__((packed));
+
+/* OpRegion mailbox #3: ASLE */
+struct opregion_asle {
+ u32 ardy; /* driver readiness */
+ u32 aslc; /* ASLE interrupt command */
+ u32 tche; /* technology enabled indicator */
+ u32 alsi; /* current ALS illuminance reading */
+ u32 bclp; /* backlight brightness to set */
+ u32 pfit; /* panel fitting state */
+ u32 cblv; /* current brightness level */
+ u16 bclm[20]; /* backlight level duty cycle mapping table */
+ u32 cpfm; /* current panel fitting mode */
+ u32 epfm; /* enabled panel fitting modes */
+ u8 plut[74]; /* panel LUT and identifier */
+ u32 pfmb; /* PWM freq and min brightness */
+ u8 rsvd[102];
+} __attribute__((packed));
+
+/* ASLE irq request bits */
+#define ASLE_SET_ALS_ILLUM (1 << 0)
+#define ASLE_SET_BACKLIGHT (1 << 1)
+#define ASLE_SET_PFIT (1 << 2)
+#define ASLE_SET_PWM_FREQ (1 << 3)
+#define ASLE_REQ_MSK 0xf
+
+/* response bits of ASLE irq request */
+#define ASLE_ALS_ILLUM_FAIL (2<<10)
+#define ASLE_BACKLIGHT_FAIL (2<<12)
+#define ASLE_PFIT_FAIL (2<<14)
+#define ASLE_PWM_FREQ_FAIL (2<<16)
+
+/* ASLE backlight brightness to set */
+#define ASLE_BCLP_VALID (1<<31)
+#define ASLE_BCLP_MSK (~(1<<31))
+
+/* ASLE panel fitting request */
+#define ASLE_PFIT_VALID (1<<31)
+#define ASLE_PFIT_CENTER (1<<0)
+#define ASLE_PFIT_STRETCH_TEXT (1<<1)
+#define ASLE_PFIT_STRETCH_GFX (1<<2)
+
+/* PWM frequency and minimum brightness */
+#define ASLE_PFMB_BRIGHTNESS_MASK (0xff)
+#define ASLE_PFMB_BRIGHTNESS_VALID (1<<8)
+#define ASLE_PFMB_PWM_MASK (0x7ffffe00)
+#define ASLE_PFMB_PWM_VALID (1<<31)
+
+#define ASLE_CBLV_VALID (1<<31)
+
+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;
+
+ if (!(bclp & ASLE_BCLP_VALID))
+ return ASLE_BACKLIGHT_FAIL;
+
+ bclp &= ASLE_BCLP_MSK;
+ if (bclp < 0 || bclp > 255)
+ return ASLE_BACKLIGHT_FAIL;
+
+ blc_pwm_ctl = I915_READ(BLC_PWM_CTL);
+ blc_pwm_ctl &= ~BACKLIGHT_DUTY_CYCLE_MASK;
+ blc_pwm_ctl2 = I915_READ(BLC_PWM_CTL2);
+
+ if (blc_pwm_ctl2 & BLM_COMBINATION_MODE)
+ pci_write_config_dword(dev->pdev, PCI_LBPC, bclp);
+ else
+ I915_WRITE(BLC_PWM_CTL, blc_pwm_ctl | ((bclp * 0x101)-1));
+
+ asle->cblv = (bclp*0x64)/0xff | ASLE_CBLV_VALID;
+
+ return 0;
+}
+
+static u32 asle_set_als_illum(struct drm_device *dev, u32 alsi)
+{
+ /* alsi is the current ALS reading in lux. 0 indicates below sensor
+ range, 0xffff indicates above sensor range. 1-0xfffe are valid */
+ return 0;
+}
+
+static u32 asle_set_pwm_freq(struct drm_device *dev, u32 pfmb)
+{
+ struct drm_i915_private *dev_priv = dev->dev_private;
+ if (pfmb & ASLE_PFMB_PWM_VALID) {
+ u32 blc_pwm_ctl = I915_READ(BLC_PWM_CTL);
+ u32 pwm = pfmb & ASLE_PFMB_PWM_MASK;
+ blc_pwm_ctl &= BACKLIGHT_DUTY_CYCLE_MASK;
+ pwm = pwm >> 9;
+ /* FIXME - what do we do with the PWM? */
+ }
+ return 0;
+}
+
+static u32 asle_set_pfit(struct drm_device *dev, u32 pfit)
+{
+ /* Panel fitting is currently controlled by the X code, so this is a
+ noop until modesetting support works fully */
+ if (!(pfit & ASLE_PFIT_VALID))
+ return ASLE_PFIT_FAIL;
+ return 0;
+}
+
+void opregion_asle_intr(struct drm_device *dev)
+{
+ struct drm_i915_private *dev_priv = dev->dev_private;
+ struct opregion_asle *asle = dev_priv->opregion.asle;
+ u32 asle_stat = 0;
+ u32 asle_req;
+
+ if (!asle)
+ return;
+
+ asle_req = asle->aslc & ASLE_REQ_MSK;
+
+ if (!asle_req) {
+ DRM_DEBUG("non asle set request??\n");
+ return;
+ }
+
+ if (asle_req & ASLE_SET_ALS_ILLUM)
+ asle_stat |= asle_set_als_illum(dev, asle->alsi);
+
+ if (asle_req & ASLE_SET_BACKLIGHT)
+ asle_stat |= asle_set_backlight(dev, asle->bclp);
+
+ if (asle_req & ASLE_SET_PFIT)
+ asle_stat |= asle_set_pfit(dev, asle->pfit);
+
+ if (asle_req & ASLE_SET_PWM_FREQ)
+ asle_stat |= asle_set_pwm_freq(dev, asle->pfmb);
+
+ asle->aslc = asle_stat;
+}
+
+#define ASLE_ALS_EN (1<<0)
+#define ASLE_BLC_EN (1<<1)
+#define ASLE_PFIT_EN (1<<2)
+#define ASLE_PFMB_EN (1<<3)
+
+void opregion_enable_asle(struct drm_device *dev)
+{
+ struct drm_i915_private *dev_priv = dev->dev_private;
+ struct opregion_asle *asle = dev_priv->opregion.asle;
+
+ if (asle) {
+ u32 pipeb_stats = I915_READ(PIPEBSTAT);
+ if (IS_MOBILE(dev)) {
+ /* Many devices trigger events with a write to the
+ legacy backlight controller, so we need to ensure
+ that it's able to generate interrupts */
+ I915_WRITE(PIPEBSTAT, pipeb_stats |=
+ I915_LEGACY_BLC_EVENT_ENABLE);
+ i915_enable_irq(dev_priv, I915_ASLE_INTERRUPT |
+ I915_DISPLAY_PIPE_B_EVENT_INTERRUPT);
+ } else
+ i915_enable_irq(dev_priv, I915_ASLE_INTERRUPT);
+
+ asle->tche = ASLE_ALS_EN | ASLE_BLC_EN | ASLE_PFIT_EN |
+ ASLE_PFMB_EN;
+ asle->ardy = 1;
+ }
+}
+
+#define ACPI_EV_DISPLAY_SWITCH (1<<0)
+#define ACPI_EV_LID (1<<1)
+#define ACPI_EV_DOCK (1<<2)
+
+static struct intel_opregion *system_opregion;
+
+int intel_opregion_video_event(struct notifier_block *nb, unsigned long val,
+ void *data)
+{
+ /* The only video events relevant to opregion are 0x80. These indicate
+ either a docking event, lid switch or display switch request. In
+ Linux, these are handled by the dock, button and video drivers.
+ We might want to fix the video driver to be opregion-aware in
+ future, but right now we just indicate to the firmware that the
+ request has been handled */
+
+ struct opregion_acpi *acpi;
+
+ if (!system_opregion)
+ return NOTIFY_DONE;
+
+ acpi = system_opregion->acpi;
+ acpi->csts = 0;
+
+ return NOTIFY_OK;
+}
+
+static struct notifier_block intel_opregion_notifier = {
+ .notifier_call = intel_opregion_video_event,
+};
+
+int intel_opregion_init(struct drm_device *dev)
+{
+ struct drm_i915_private *dev_priv = dev->dev_private;
+ struct intel_opregion *opregion = &dev_priv->opregion;
+ void *base;
+ u32 asls, mboxes;
+ int err = 0;
+
+ pci_read_config_dword(dev->pdev, PCI_ASLS, &asls);
+ DRM_DEBUG("graphic opregion physical addr: 0x%x\n", asls);
+ if (asls == 0) {
+ DRM_DEBUG("ACPI OpRegion not supported!\n");
+ return -ENOTSUPP;
+ }
+
+ base = ioremap(asls, OPREGION_SZ);
+ if (!base)
+ return -ENOMEM;
+
+ opregion->header = base;
+ if (memcmp(opregion->header->signature, OPREGION_SIGNATURE, 16)) {
+ DRM_DEBUG("opregion signature mismatch\n");
+ err = -EINVAL;
+ goto err_out;
+ }
+
+ mboxes = opregion->header->mboxes;
+ if (mboxes & MBOX_ACPI) {
+ DRM_DEBUG("Public ACPI methods supported\n");
+ opregion->acpi = base + OPREGION_ACPI_OFFSET;
+ } else {
+ DRM_DEBUG("Public ACPI methods not supported\n");
+ err = -ENOTSUPP;
+ goto err_out;
+ }
+ opregion->enabled = 1;
+
+ if (mboxes & MBOX_SWSCI) {
+ DRM_DEBUG("SWSCI supported\n");
+ opregion->swsci = base + OPREGION_SWSCI_OFFSET;
+ }
+ if (mboxes & MBOX_ASLE) {
+ DRM_DEBUG("ASLE supported\n");
+ opregion->asle = base + OPREGION_ASLE_OFFSET;
+ }
+
+ /* Notify BIOS we are ready to handle ACPI video ext notifs.
+ * Right now, all the events are handled by the ACPI video module.
+ * We don't actually need to do anything with them. */
+ opregion->acpi->csts = 0;
+ opregion->acpi->drdy = 1;
+
+ system_opregion = opregion;
+ register_acpi_notifier(&intel_opregion_notifier);
+
+ return 0;
+
+err_out:
+ iounmap(opregion->header);
+ opregion->header = NULL;
+ return err;
+}
+
+void intel_opregion_free(struct drm_device *dev)
+{
+ struct drm_i915_private *dev_priv = dev->dev_private;
+ struct intel_opregion *opregion = &dev_priv->opregion;
+
+ if (!opregion->enabled)
+ return;
+
+ opregion->acpi->drdy = 0;
+
+ system_opregion = NULL;
+ unregister_acpi_notifier(&intel_opregion_notifier);
+
+ /* just clear all opregion memory pointers now */
+ iounmap(opregion->header);
+ opregion->header = NULL;
+ opregion->acpi = NULL;
+ opregion->swsci = NULL;
+ opregion->asle = NULL;
+
+ opregion->enabled = 0;
+}
diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 477c64e6ba2..43ad2cb8b9f 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -740,6 +740,7 @@
#define BLC_PWM_CTL 0x61254
#define BACKLIGHT_MODULATION_FREQ_SHIFT (17)
#define BLC_PWM_CTL2 0x61250 /* 965+ only */
+#define BLM_COMBINATION_MODE (1 << 30)
/*
* This is the most significant 15 bits of the number of backlight cycles in a
* complete cycle of the modulated backlight control.