[RFC] drm/i915: downclock support
diff mbox

Message ID 20090727165536.GA10181@srcf.ucam.org
State RFC
Headers show

Commit Message

Matthew Garrett July 27, 2009, 4:55 p.m. UTC
Here's my current version - tested working on 945 and 965.

commit 914cbeb9dee6a75140a79b617206a6f7b253593e
Author: Matthew Garrett <mjg59@vaio.localdomain>
Date:   Sun Jul 26 19:40:21 2009 +0100

    drm: Add dynamic power management to Intel
    
    There are several sources of unnecessary power consumption on Intel
    graphics systems. The first is the LVDS clock. TFTs don't suffer from
    persistence issues like TFTs, and so we can reduce the LVDS refresh
    rate when the screen is idle. It will be automatically upclocked when
    userspace triggers graphical activity. Beyond that, we can enable
    memory self refresh. This allows the memory to go into a lower power state
    when the graphics are idle. Finally, we can drop some clocks on the gpu
    itself. All of these things can be reenabled between frames, and so there
    should be no user visible graphical changes.
    
    Signed-off-by: Jesse Barnes <jesse.barnes@intel.com>
    Signed-off-by: Matthew Garrett <mjg@redhat.com>

Comments

Keith Packard July 27, 2009, 5:27 p.m. UTC | #1
On Mon, 2009-07-27 at 17:55 +0100, Matthew Garrett wrote:

>  static int intel_crtc_cursor_move(struct drm_crtc *crtc, int x, int y)
>  {
>  	struct drm_device *dev = crtc->dev;
> @@ -2557,6 +2661,12 @@ static int intel_crtc_cursor_move(struct drm_crtc *crtc, int x, int y)
>  	uint32_t temp = 0;
>  	uint32_t adder;
>  
> +	if (!intel_crtc->busy)
> +		intel_increase_pllclock(crtc, true);
> +	intel_crtc->busy = true;
> +	mod_timer(&intel_crtc->idle_timer, jiffies +
> +		  msecs_to_jiffies(CRTC_IDLE_TIMEOUT));
> +
>  	if (x < 0) {
>  		temp |= CURSOR_POS_SIGN << CURSOR_X_SHIFT;
>  		x = -x;

> +void intel_mark_busy(struct drm_device *dev, struct drm_gem_object *obj)

> +		if (intel_fb->obj == obj) {
> +			if (!intel_crtc->busy)
> +				intel_increase_pllclock(crtc, true);
> +			intel_crtc->busy = true;
> +			mod_timer(&intel_crtc->idle_timer, jiffies +
> +				  msecs_to_jiffies(CRTC_IDLE_TIMEOUT));
> +		}

Merge these two pieces of identical code?
Rémi Cardona July 27, 2009, 5:43 p.m. UTC | #2
Le 27/07/2009 18:55, Matthew Garrett a écrit :
>      TFTs don't suffer from
>      persistence issues like TFTs,

Probably meant CRTs instead of the second "TFTs" ?

Rémi
Fu Michael Aug. 27, 2009, 7:16 a.m. UTC | #3
Matthew Garrett wrote:
> Here's my current version - tested working on 945 and 965.
>
> commit 914cbeb9dee6a75140a79b617206a6f7b253593e
> Author: Matthew Garrett <mjg59@vaio.localdomain>
> Date:   Sun Jul 26 19:40:21 2009 +0100
>
>     drm: Add dynamic power management to Intel
>     
>     There are several sources of unnecessary power consumption on Intel
>     graphics systems. The first is the LVDS clock. TFTs don't suffer from
>     persistence issues like TFTs, and so we can reduce the LVDS refresh
>     rate when the screen is idle. It will be automatically upclocked when
>     userspace triggers graphical activity. Beyond that, we can enable
>     memory self refresh. This allows the memory to go into a lower power state
>     when the graphics are idle. Finally, we can drop some clocks on the gpu
>     itself. All of these things can be reenabled between frames, and so there
>     should be no user visible graphical changes.
>     
>     Signed-off-by: Jesse Barnes <jesse.barnes@intel.com>
>     Signed-off-by: Matthew Garrett <mjg@redhat.com>
>
> diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
> index a58bfad..f9984fe 100644
> --- a/drivers/gpu/drm/i915/intel_display.c
> +++ b/drivers/gpu/drm/i915/intel_display.c
> @@ -190,7 +193,7 @@ struct intel_limit {
>  #define G4X_P2_SINGLE_CHANNEL_LVDS_LIMIT          0
>  
>  /*The parameter is for DUAL_CHANNEL_LVDS on G4x platform*/
> -#define G4X_DOT_DUAL_CHANNEL_LVDS_MIN           80000
> +#define G4X_DOT_DUAL_CHANNEL_LVDS_MIN           20000
>   
this looks wrong. 80000 is correct for G4x. Where does the 20000 come from?


> @@ -666,15 +682,16 @@ intel_find_best_PLL(const intel_limit_t *limit, struct drm_crtc *crtc,
>  
>  	memset (best_clock, 0, sizeof (*best_clock));
>  
> -	for (clock.m1 = limit->m1.min; clock.m1 <= limit->m1.max; clock.m1++) {
> -		for (clock.m2 = limit->m2.min; clock.m2 <= limit->m2.max; clock.m2++) {
> -			/* m1 is always 0 in IGD */
> -			if (clock.m2 >= clock.m1 && !IS_IGD(dev))
> -				break;
> -			for (clock.n = limit->n.min; clock.n <= limit->n.max;
> -			     clock.n++) {
> -				for (clock.p1 = limit->p1.min;
> -				     clock.p1 <= limit->p1.max; clock.p1++) {
> +	for (clock.p1 = limit->p1.max; clock.p1 >= limit->p1.min; clock.p1--) {
> +		for (clock.m1 = limit->m1.min; clock.m1 <= limit->m1.max;
> +		     clock.m1++) {
> +			for (clock.m2 = limit->m2.min;
> +			     clock.m2 <= limit->m2.max; clock.m2++) {
> +				/* m1 is always 0 in IGD */
> +				if (clock.m2 >= clock.m1 && !IS_IGD(dev))
> +					break;
> +				for (clock.n = limit->n.min;
> +				     clock.n <= limit->n.max; clock.n++) {
>  					int this_err;
>  
>   
I don't see why this change is needed.  Are there any bug using the old 
code?
Keith Packard Aug. 27, 2009, 3:24 p.m. UTC | #4
On Thu, 2009-08-27 at 15:16 +0800, Fu Michael wrote:
>   
> I don't see why this change is needed.  Are there any bug using the old 
> code?

No, not if you wanted only a single clock. However, downclocking can
only modify the P parameter, not the M or N values. So, choosing a PLL
programming that has the largest possible P means being able to
downclock successfully.
Zhao, Yakui Aug. 29, 2009, 1:17 a.m. UTC | #5
On Thu, 2009-08-27 at 23:24 +0800, Keith Packard wrote:
> On Thu, 2009-08-27 at 15:16 +0800, Fu Michael wrote:
> >   
> > I don't see why this change is needed.  Are there any bug using the old 
> > code?
> 
> No, not if you wanted only a single clock. However, downclocking can
> only modify the P parameter, not the M or N values. So, choosing a PLL
> programming that has the largest possible P means being able to
> downclock successfully.
According to the spec the mutiply of P1 and P2 will be P. And the value
of P2 is fixed. Then only P1 can be changed to change the value of P.

If we only changes P1, maybe the calculated VCO will be beyond the VCO
limit.

So IMO it is inappropriate to downclock by only changing the P value.

thanks.
> 
>
Fu Michael Aug. 31, 2009, 8:08 a.m. UTC | #6
Keith Packard wrote:
> On Thu, 2009-08-27 at 15:16 +0800, Fu Michael wrote:
>   
>>   
>> I don't see why this change is needed.  Are there any bug using the old 
>> code?
>>     
>
> No, not if you wanted only a single clock. However, downclocking can
> only modify the P parameter, not the M or N values. So, choosing a PLL
> programming that has the largest possible P means being able to
> downclock successfully.
>
>   
looks like the code change FP0/1 which controls M,N , instead of P.. But 
I get your point that bigger P gives better chance to find smaller M/N, 
if we want smaller dot clock. However, the lesson we learned in the past 
( and also confirmed by arch team ) is that for a given dot clock, there 
is only _one_ combination of M,N,P that generate the right clock, _not_ 
any combination that mathematically correct will do. that's why loop 
from big end or little end matters in the find_dpll func.

In the mean time, do we have to set reduced_clock=current_clock*3/4? 
could other clocks work?

Patch
diff mbox

diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
index fc4b68a..ea388fb 100644
--- a/drivers/gpu/drm/i915/i915_drv.c
+++ b/drivers/gpu/drm/i915/i915_drv.c
@@ -43,6 +43,9 @@  module_param_named(modeset, i915_modeset, int, 0400);
 unsigned int i915_fbpercrtc = 0;
 module_param_named(fbpercrtc, i915_fbpercrtc, int, 0400);
 
+unsigned int i915_powersave = 1;
+module_param_named(powersave, i915_powersave, int, 0400);
+
 static struct drm_driver driver;
 
 static struct pci_device_id pciidlist[] = {
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index b05b44d..5cd915b 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -437,6 +437,12 @@  typedef struct drm_i915_private {
 		struct drm_i915_gem_phys_object *phys_objs[I915_MAX_PHYS_OBJECT];
 	} mm;
 	struct sdvo_device_mapping sdvo_mappings[2];
+
+	/* Reclocking support */
+	struct work_struct idle_work;
+	struct timer_list idle_timer;
+	bool busy;
+	u16 orig_clock;
 } drm_i915_private_t;
 
 /** driver private structure attached to each drm_gem_object */
@@ -566,6 +572,7 @@  enum intel_chip_family {
 extern struct drm_ioctl_desc i915_ioctls[];
 extern int i915_max_ioctl;
 extern unsigned int i915_fbpercrtc;
+extern unsigned int i915_powersave;
 
 extern int i915_master_create(struct drm_device *dev, struct drm_master *master);
 extern void i915_master_destroy(struct drm_device *dev, struct drm_master *master);
@@ -893,6 +900,9 @@  extern int i915_wait_ring(struct drm_device * dev, int n, const char *caller);
 /* dsparb controlled by hw only */
 #define DSPARB_HWCONTROL(dev) (IS_G4X(dev) || IS_IGDNG(dev))
 
+#define HAS_FW_BLC(dev) (IS_I9XX(dev) || IS_G4X(dev) || IS_IGDNG(dev))
+#define HAS_PIPE_CXSR(dev) (IS_G4X(dev) || IS_IGDNG(dev))
+
 #define PRIMARY_RINGBUFFER_SIZE         (128*1024)
 
 #endif
diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 5bf4203..ce2d9b8 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -29,6 +29,7 @@ 
 #include "drm.h"
 #include "i915_drm.h"
 #include "i915_drv.h"
+#include "intel_drv.h"
 #include <linux/swap.h>
 #include <linux/pci.h>
 
@@ -980,6 +981,7 @@  i915_gem_set_domain_ioctl(struct drm_device *dev, void *data,
 {
 	struct drm_i915_gem_set_domain *args = data;
 	struct drm_gem_object *obj;
+	struct drm_i915_gem_object *obj_priv;
 	uint32_t read_domains = args->read_domains;
 	uint32_t write_domain = args->write_domain;
 	int ret;
@@ -1003,8 +1005,12 @@  i915_gem_set_domain_ioctl(struct drm_device *dev, void *data,
 	obj = drm_gem_object_lookup(dev, file_priv, args->handle);
 	if (obj == NULL)
 		return -EBADF;
+	obj_priv = obj->driver_private;
 
 	mutex_lock(&dev->struct_mutex);
+
+	intel_mark_busy(dev, obj);
+
 #if WATCH_BUF
 	DRM_INFO("set_domain_ioctl %p(%zd), %08x %08x\n",
 		 obj, obj->size, read_domains, write_domain);
@@ -2761,6 +2767,8 @@  i915_gem_object_set_to_gpu_domain(struct drm_gem_object *obj)
 	BUG_ON(obj->pending_read_domains & I915_GEM_DOMAIN_CPU);
 	BUG_ON(obj->pending_write_domain == I915_GEM_DOMAIN_CPU);
 
+	intel_mark_busy(dev, obj);
+
 #if WATCH_BUF
 	DRM_INFO("%s: object %p read %08x -> %08x write %08x -> %08x\n",
 		 __func__, obj,
diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index 897a116..9db90b4 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -55,7 +55,7 @@ 
 /* PCI config space */
 
 #define HPLLCC	0xc0 /* 855 only */
-#define   GC_CLOCK_CONTROL_MASK		(3 << 0)
+#define   GC_CLOCK_CONTROL_MASK		(0xf << 0)
 #define   GC_CLOCK_133_200		(0 << 0)
 #define   GC_CLOCK_100_200		(1 << 0)
 #define   GC_CLOCK_100_133		(2 << 0)
@@ -65,6 +65,25 @@ 
 #define   GC_DISPLAY_CLOCK_190_200_MHZ	(0 << 4)
 #define   GC_DISPLAY_CLOCK_333_MHZ	(4 << 4)
 #define   GC_DISPLAY_CLOCK_MASK		(7 << 4)
+#define   GM45_GC_RENDER_CLOCK_MASK	(0xf << 0)
+#define   GM45_GC_RENDER_CLOCK_266_MHZ	(8 << 0)
+#define   GM45_GC_RENDER_CLOCK_320_MHZ	(9 << 0)
+#define   GM45_GC_RENDER_CLOCK_400_MHZ	(0xb << 0)
+#define   GM45_GC_RENDER_CLOCK_533_MHZ	(0xc << 0)
+#define   I965_GC_RENDER_CLOCK_MASK	(0xf << 0)
+#define   I965_GC_RENDER_CLOCK_267_MHZ	(2 << 0)
+#define   I965_GC_RENDER_CLOCK_333_MHZ	(3 << 0)
+#define   I965_GC_RENDER_CLOCK_444_MHZ	(4 << 0)
+#define   I965_GC_RENDER_CLOCK_533_MHZ	(5 << 0)
+#define   I945_GC_RENDER_CLOCK_MASK	(7 << 0)
+#define   I945_GC_RENDER_CLOCK_166_MHZ	(0 << 0)
+#define   I945_GC_RENDER_CLOCK_200_MHZ	(1 << 0)
+#define   I945_GC_RENDER_CLOCK_250_MHZ	(3 << 0)
+#define   I945_GC_RENDER_CLOCK_400_MHZ	(5 << 0)
+#define   I915_GC_RENDER_CLOCK_MASK	(7 << 0)
+#define   I915_GC_RENDER_CLOCK_166_MHZ	(0 << 0)
+#define   I915_GC_RENDER_CLOCK_200_MHZ	(1 << 0)
+#define   I915_GC_RENDER_CLOCK_333_MHZ	(4 << 0)
 #define LBB	0xf4
 
 /* VGA stuff */
@@ -1569,6 +1588,7 @@ 
 #define   PIPECONF_PROGRESSIVE	(0 << 21)
 #define   PIPECONF_INTERLACE_W_FIELD_INDICATION	(6 << 21)
 #define   PIPECONF_INTERLACE_FIELD_0_ONLY		(7 << 21)
+#define   PIPECONF_CXSR_DOWNCLOCK	(1<<16)
 #define PIPEASTAT		0x70024
 #define   PIPE_FIFO_UNDERRUN_STATUS		(1UL<<31)
 #define   PIPE_CRC_ERROR_ENABLE			(1UL<<29)
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index a58bfad..f9984fe 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -36,6 +36,7 @@ 
 
 bool intel_pipe_has_type (struct drm_crtc *crtc, int type);
 static void intel_update_watermarks(struct drm_device *dev);
+static void intel_increase_pllclock(struct drm_crtc *crtc, int schedule);
 
 typedef struct {
     /* given values */
@@ -65,6 +66,8 @@  struct intel_limit {
     intel_p2_t	    p2;
     bool (* find_pll)(const intel_limit_t *, struct drm_crtc *,
 		      int, int, intel_clock_t *);
+    bool (* find_reduced_pll)(const intel_limit_t *, struct drm_crtc *,
+			      int, int, intel_clock_t *);
 };
 
 #define I8XX_DOT_MIN		  25000
@@ -190,7 +193,7 @@  struct intel_limit {
 #define G4X_P2_SINGLE_CHANNEL_LVDS_LIMIT          0
 
 /*The parameter is for DUAL_CHANNEL_LVDS on G4x platform*/
-#define G4X_DOT_DUAL_CHANNEL_LVDS_MIN           80000
+#define G4X_DOT_DUAL_CHANNEL_LVDS_MIN           20000
 #define G4X_DOT_DUAL_CHANNEL_LVDS_MAX           224000
 #define G4X_N_DUAL_CHANNEL_LVDS_MIN             1
 #define G4X_N_DUAL_CHANNEL_LVDS_MAX             3
@@ -259,6 +262,9 @@  static bool
 intel_find_best_PLL(const intel_limit_t *limit, struct drm_crtc *crtc,
 		    int target, int refclk, intel_clock_t *best_clock);
 static bool
+intel_find_best_reduced_PLL(const intel_limit_t *limit, struct drm_crtc *crtc,
+			    int target, int refclk, intel_clock_t *best_clock);
+static bool
 intel_g4x_find_best_PLL(const intel_limit_t *limit, struct drm_crtc *crtc,
 			int target, int refclk, intel_clock_t *best_clock);
 static bool
@@ -281,6 +287,7 @@  static const intel_limit_t intel_limits_i8xx_dvo = {
 	.p2  = { .dot_limit = I8XX_P2_SLOW_LIMIT,
 		 .p2_slow = I8XX_P2_SLOW,	.p2_fast = I8XX_P2_FAST },
 	.find_pll = intel_find_best_PLL,
+	.find_reduced_pll = intel_find_best_reduced_PLL,
 };
 
 static const intel_limit_t intel_limits_i8xx_lvds = {
@@ -295,6 +302,7 @@  static const intel_limit_t intel_limits_i8xx_lvds = {
 	.p2  = { .dot_limit = I8XX_P2_SLOW_LIMIT,
 		 .p2_slow = I8XX_P2_LVDS_SLOW,	.p2_fast = I8XX_P2_LVDS_FAST },
 	.find_pll = intel_find_best_PLL,
+	.find_reduced_pll = intel_find_best_reduced_PLL,
 };
 	
 static const intel_limit_t intel_limits_i9xx_sdvo = {
@@ -309,6 +317,7 @@  static const intel_limit_t intel_limits_i9xx_sdvo = {
 	.p2  = { .dot_limit = I9XX_P2_SDVO_DAC_SLOW_LIMIT,
 		 .p2_slow = I9XX_P2_SDVO_DAC_SLOW,	.p2_fast = I9XX_P2_SDVO_DAC_FAST },
 	.find_pll = intel_find_best_PLL,
+	.find_reduced_pll = intel_find_best_reduced_PLL,
 };
 
 static const intel_limit_t intel_limits_i9xx_lvds = {
@@ -326,6 +335,7 @@  static const intel_limit_t intel_limits_i9xx_lvds = {
 	.p2  = { .dot_limit = I9XX_P2_LVDS_SLOW_LIMIT,
 		 .p2_slow = I9XX_P2_LVDS_SLOW,	.p2_fast = I9XX_P2_LVDS_FAST },
 	.find_pll = intel_find_best_PLL,
+	.find_reduced_pll = intel_find_best_reduced_PLL,
 };
 
     /* below parameter and function is for G4X Chipset Family*/
@@ -343,6 +353,7 @@  static const intel_limit_t intel_limits_g4x_sdvo = {
 		 .p2_fast = G4X_P2_SDVO_FAST
 	},
 	.find_pll = intel_g4x_find_best_PLL,
+	.find_reduced_pll = intel_g4x_find_best_PLL,
 };
 
 static const intel_limit_t intel_limits_g4x_hdmi = {
@@ -359,6 +370,7 @@  static const intel_limit_t intel_limits_g4x_hdmi = {
 		 .p2_fast = G4X_P2_HDMI_DAC_FAST
 	},
 	.find_pll = intel_g4x_find_best_PLL,
+	.find_reduced_pll = intel_g4x_find_best_PLL,
 };
 
 static const intel_limit_t intel_limits_g4x_single_channel_lvds = {
@@ -383,6 +395,7 @@  static const intel_limit_t intel_limits_g4x_single_channel_lvds = {
 		 .p2_fast = G4X_P2_SINGLE_CHANNEL_LVDS_FAST
 	},
 	.find_pll = intel_g4x_find_best_PLL,
+	.find_reduced_pll = intel_g4x_find_best_PLL,
 };
 
 static const intel_limit_t intel_limits_g4x_dual_channel_lvds = {
@@ -407,6 +420,7 @@  static const intel_limit_t intel_limits_g4x_dual_channel_lvds = {
 		 .p2_fast = G4X_P2_DUAL_CHANNEL_LVDS_FAST
 	},
 	.find_pll = intel_g4x_find_best_PLL,
+	.find_reduced_pll = intel_g4x_find_best_PLL,
 };
 
 static const intel_limit_t intel_limits_g4x_display_port = {
@@ -444,6 +458,7 @@  static const intel_limit_t intel_limits_igd_sdvo = {
 	.p2  = { .dot_limit = I9XX_P2_SDVO_DAC_SLOW_LIMIT,
 		 .p2_slow = I9XX_P2_SDVO_DAC_SLOW,	.p2_fast = I9XX_P2_SDVO_DAC_FAST },
 	.find_pll = intel_find_best_PLL,
+	.find_reduced_pll = intel_find_best_reduced_PLL,
 };
 
 static const intel_limit_t intel_limits_igd_lvds = {
@@ -459,6 +474,7 @@  static const intel_limit_t intel_limits_igd_lvds = {
 	.p2  = { .dot_limit = I9XX_P2_LVDS_SLOW_LIMIT,
 		 .p2_slow = I9XX_P2_LVDS_SLOW,	.p2_fast = I9XX_P2_LVDS_SLOW },
 	.find_pll = intel_find_best_PLL,
+	.find_reduced_pll = intel_find_best_reduced_PLL,
 };
 
 static const intel_limit_t intel_limits_igdng_sdvo = {
@@ -666,15 +682,16 @@  intel_find_best_PLL(const intel_limit_t *limit, struct drm_crtc *crtc,
 
 	memset (best_clock, 0, sizeof (*best_clock));
 
-	for (clock.m1 = limit->m1.min; clock.m1 <= limit->m1.max; clock.m1++) {
-		for (clock.m2 = limit->m2.min; clock.m2 <= limit->m2.max; clock.m2++) {
-			/* m1 is always 0 in IGD */
-			if (clock.m2 >= clock.m1 && !IS_IGD(dev))
-				break;
-			for (clock.n = limit->n.min; clock.n <= limit->n.max;
-			     clock.n++) {
-				for (clock.p1 = limit->p1.min;
-				     clock.p1 <= limit->p1.max; clock.p1++) {
+	for (clock.p1 = limit->p1.max; clock.p1 >= limit->p1.min; clock.p1--) {
+		for (clock.m1 = limit->m1.min; clock.m1 <= limit->m1.max;
+		     clock.m1++) {
+			for (clock.m2 = limit->m2.min;
+			     clock.m2 <= limit->m2.max; clock.m2++) {
+				/* m1 is always 0 in IGD */
+				if (clock.m2 >= clock.m1 && !IS_IGD(dev))
+					break;
+				for (clock.n = limit->n.min;
+				     clock.n <= limit->n.max; clock.n++) {
 					int this_err;
 
 					intel_clock(dev, refclk, &clock);
@@ -695,6 +712,46 @@  intel_find_best_PLL(const intel_limit_t *limit, struct drm_crtc *crtc,
 	return (err != target);
 }
 
+
+static bool
+intel_find_best_reduced_PLL(const intel_limit_t *limit, struct drm_crtc *crtc,
+			    int target, int refclk, intel_clock_t *best_clock)
+
+{
+	struct drm_device *dev = crtc->dev;
+	intel_clock_t clock;
+	int err = target;
+	bool found = false;
+
+	memcpy(&clock, best_clock, sizeof(intel_clock_t));
+
+	for (clock.m1 = limit->m1.min; clock.m1 <= limit->m1.max; clock.m1++) {
+		for (clock.m2 = limit->m2.min; clock.m2 <= limit->m2.max; clock.m2++) {
+			/* m1 is always 0 in IGD */
+			if (clock.m2 >= clock.m1 && !IS_IGD(dev))
+				break;
+			for (clock.n = limit->n.min; clock.n <= limit->n.max;
+			     clock.n++) {
+				int this_err;
+
+				intel_clock(dev, refclk, &clock);
+
+				if (!intel_PLL_is_valid(crtc, &clock))
+					continue;
+
+				this_err = abs(clock.dot - target);
+				if (this_err < err) {
+					*best_clock = clock;
+					err = this_err;
+					found = true;
+				}
+			}
+		}
+	}
+
+	return found;
+}
+
 static bool
 intel_g4x_find_best_PLL(const intel_limit_t *limit, struct drm_crtc *crtc,
 			int target, int refclk, intel_clock_t *best_clock)
@@ -725,7 +782,7 @@  intel_g4x_find_best_PLL(const intel_limit_t *limit, struct drm_crtc *crtc,
 	max_n = limit->n.max;
 	/* based on hardware requriment prefer smaller n to precision */
 	for (clock.n = limit->n.min; clock.n <= max_n; clock.n++) {
-		/* based on hardware requirment prefere larger m1,m2, p1 */
+		/* based on hardware requirment prefere larger m1,m2 */
 		for (clock.m1 = limit->m1.max;
 		     clock.m1 >= limit->m1.min; clock.m1--) {
 			for (clock.m2 = limit->m2.max;
@@ -735,8 +792,8 @@  intel_g4x_find_best_PLL(const intel_limit_t *limit, struct drm_crtc *crtc,
 					int this_err;
 
 					intel_clock(dev, refclk, &clock);
-					if (!intel_PLL_is_valid(crtc, &clock))
-						continue;
+					if (!intel_PLL_is_valid(crtc, &clock))
+						continue;
 					this_err = abs(clock.dot - target) ;
 					if (this_err < err_most) {
 						*best_clock = clock;
@@ -778,15 +835,14 @@  intel_igdng_find_best_PLL(const intel_limit_t *limit, struct drm_crtc *crtc,
 
 	memset(best_clock, 0, sizeof(*best_clock));
 	max_n = limit->n.max;
-	/* based on hardware requriment prefer smaller n to precision */
-	for (clock.n = limit->n.min; clock.n <= max_n; clock.n++) {
-		/* based on hardware requirment prefere larger m1,m2, p1 */
-		for (clock.m1 = limit->m1.max;
-		     clock.m1 >= limit->m1.min; clock.m1--) {
-			for (clock.m2 = limit->m2.max;
-			     clock.m2 >= limit->m2.min; clock.m2--) {
-				for (clock.p1 = limit->p1.max;
-				     clock.p1 >= limit->p1.min; clock.p1--) {
+	for (clock.p1 = limit->p1.max; clock.p1 >= limit->p1.min; clock.p1--) {
+		/* based on hardware requriment prefer smaller n to precision */
+		for (clock.n = limit->n.min; clock.n <= max_n; clock.n++) {
+			/* based on hardware requirment prefere larger m1,m2 */
+			for (clock.m1 = limit->m1.max;
+			     clock.m1 >= limit->m1.min; clock.m1--) {
+				for (clock.m2 = limit->m2.max;
+				     clock.m2 >= limit->m2.min; clock.m2--) {
 					int this_err;
 
 					intel_clock(dev, refclk, &clock);
@@ -976,8 +1032,11 @@  intel_pipe_set_base(struct drm_crtc *crtc, int x, int y,
 
 	if (old_fb) {
 		intel_fb = to_intel_framebuffer(old_fb);
+		obj_priv = intel_fb->obj->driver_private;
 		i915_gem_object_unpin(intel_fb->obj);
 	}
+	intel_increase_pllclock(crtc, true);
+
 	mutex_unlock(&dev->struct_mutex);
 
 	if (!dev->primary->master)
@@ -1855,6 +1914,18 @@  static int intel_get_fifo_size(struct drm_device *dev, int plane)
 	return size;
 }
 
+static void g4x_update_wm(struct drm_device *dev)
+{
+	struct drm_i915_private *dev_priv = dev->dev_private;
+	u32 fw_blc_self = I915_READ(FW_BLC_SELF);
+
+	if (i915_powersave)
+		fw_blc_self |= FW_BLC_SELF_EN;
+	else
+		fw_blc_self &= ~FW_BLC_SELF_EN;
+	I915_WRITE(FW_BLC_SELF, fw_blc_self);
+}
+
 static void i965_update_wm(struct drm_device *dev)
 {
 	struct drm_i915_private *dev_priv = dev->dev_private;
@@ -1906,7 +1977,8 @@  static void i9xx_update_wm(struct drm_device *dev, int planea_clock,
 	cwm = 2;
 
 	/* Calc sr entries for one plane configs */
-	if (sr_hdisplay && (!planea_clock || !planeb_clock)) {
+	if (HAS_FW_BLC(dev) && sr_hdisplay &&
+	    (!planea_clock || !planeb_clock)) {
 		/* self-refresh has much higher latency */
 		const static int sr_latency_ns = 6000;
 
@@ -1921,8 +1993,7 @@  static void i9xx_update_wm(struct drm_device *dev, int planea_clock,
 		srwm = total_size - sr_entries;
 		if (srwm < 0)
 			srwm = 1;
-		if (IS_I9XX(dev))
-			I915_WRITE(FW_BLC_SELF, (srwm & 0x3f));
+		I915_WRITE(FW_BLC_SELF, FW_BLC_SELF_EN | (srwm & 0x3f));
 	}
 
 	DRM_DEBUG("Setting FIFO watermarks - A: %d, B: %d, C: %d, SR %d\n",
@@ -1994,9 +2065,6 @@  static void intel_update_watermarks(struct drm_device *dev)
 	unsigned long planea_clock = 0, planeb_clock = 0, sr_clock = 0;
 	int enabled = 0, pixel_size = 0;
 
-	if (DSPARB_HWCONTROL(dev))
-		return;
-
 	/* Get the clock config from both planes */
 	list_for_each_entry(crtc, &dev->mode_config.crtc_list, head) {
 		intel_crtc = to_intel_crtc(crtc);
@@ -2029,7 +2097,9 @@  static void intel_update_watermarks(struct drm_device *dev)
 	else if (IS_IGD(dev))
 		igd_disable_cxsr(dev);
 
-	if (IS_I965G(dev))
+	if (IS_G4X(dev))
+		g4x_update_wm(dev);
+	else if (IS_I965G(dev))
 		i965_update_wm(dev);
 	else if (IS_I9XX(dev) || IS_MOBILE(dev))
 		i9xx_update_wm(dev, planea_clock, planeb_clock, sr_hdisplay,
@@ -2063,9 +2133,9 @@  static int intel_crtc_mode_set(struct drm_crtc *crtc,
 	int dsppos_reg = (pipe == 0) ? DSPAPOS : DSPBPOS;
 	int pipesrc_reg = (pipe == 0) ? PIPEASRC : PIPEBSRC;
 	int refclk, num_outputs = 0;
-	intel_clock_t clock;
-	u32 dpll = 0, fp = 0, dspcntr, pipeconf;
-	bool ok, is_sdvo = false, is_dvo = false;
+	intel_clock_t clock, reduced_clock;
+	u32 dpll = 0, fp = 0, fp2 = 0, dspcntr, pipeconf;
+	bool ok, has_reduced_clock = false, is_sdvo = false, is_dvo = false;
 	bool is_crt = false, is_lvds = false, is_tv = false, is_dp = false;
 	struct drm_mode_config *mode_config = &dev->mode_config;
 	struct drm_connector *connector;
@@ -2143,6 +2213,14 @@  static int intel_crtc_mode_set(struct drm_crtc *crtc,
 		return -EINVAL;
 	}
 
+	if (limit->find_reduced_pll) {
+		memcpy(&reduced_clock, &clock, sizeof(intel_clock_t));
+		has_reduced_clock = limit->find_reduced_pll(limit, crtc,
+							    (adjusted_mode->clock*3/4),
+							    refclk,
+							    &reduced_clock);
+	}
+
 	/* SDVO TV has fixed PLL values depend on its clock range,
 	   this mirrors vbios setting. */
 	if (is_sdvo && is_tv) {
@@ -2170,10 +2248,17 @@  static int intel_crtc_mode_set(struct drm_crtc *crtc,
 				270000, /* lane clock */
 				&m_n);
 
-	if (IS_IGD(dev))
+	if (IS_IGD(dev)) {
 		fp = (1 << clock.n) << 16 | clock.m1 << 8 | clock.m2;
-	else
+		if (has_reduced_clock)
+			fp2 = (1 << reduced_clock.n) << 16 |
+				reduced_clock.m1 << 8 | reduced_clock.m2;
+	} else {
 		fp = clock.n << 16 | clock.m1 << 8 | clock.m2;
+		if (has_reduced_clock)
+			fp2 = reduced_clock.n << 16 | reduced_clock.m1 << 8 |
+				reduced_clock.m2;
+	}
 
 	if (!IS_IGDNG(dev))
 		dpll = DPLL_VGA_MODE_DIS;
@@ -2202,6 +2287,8 @@  static int intel_crtc_mode_set(struct drm_crtc *crtc,
 			/* also FPA1 */
 			if (IS_IGDNG(dev))
 				dpll |= (1 << (clock.p1 - 1)) << DPLL_FPA1_P1_POST_DIV_SHIFT;
+			if (IS_G4X(dev) && has_reduced_clock)
+				dpll |= (1 << (reduced_clock.p1 - 1)) << DPLL_FPA1_P1_POST_DIV_SHIFT;
 		}
 		switch (clock.p2) {
 		case 5:
@@ -2344,6 +2431,21 @@  static int intel_crtc_mode_set(struct drm_crtc *crtc,
 		intel_dp_set_m_n(crtc, mode, adjusted_mode);
 
 	I915_WRITE(fp_reg, fp);
+	if (has_reduced_clock && i915_powersave) {
+		I915_WRITE(fp_reg + 4, fp2);
+		intel_crtc->lowfreq_avail = true;
+		if (HAS_PIPE_CXSR(dev)) {
+			DRM_DEBUG("enabling CxSR downclocking\n");
+			pipeconf |= PIPECONF_CXSR_DOWNCLOCK;
+		}
+	} else {
+		I915_WRITE(fp_reg + 4, fp);
+		intel_crtc->lowfreq_avail = false;
+		if (HAS_PIPE_CXSR(dev)) {
+			DRM_DEBUG("disabling CxSR downclocking\n");
+			pipeconf &= ~PIPECONF_CXSR_DOWNCLOCK;
+		}
+	}
 	I915_WRITE(dpll_reg, dpll);
 	I915_READ(dpll_reg);
 	/* Wait for the clocks to stabilize. */
@@ -2548,6 +2650,8 @@  fail_locked:
 	return ret;
 }
 
+#define CRTC_IDLE_TIMEOUT 50 /* ms */
+
 static int intel_crtc_cursor_move(struct drm_crtc *crtc, int x, int y)
 {
 	struct drm_device *dev = crtc->dev;
@@ -2557,6 +2661,12 @@  static int intel_crtc_cursor_move(struct drm_crtc *crtc, int x, int y)
 	uint32_t temp = 0;
 	uint32_t adder;
 
+	if (!intel_crtc->busy)
+		intel_increase_pllclock(crtc, true);
+	intel_crtc->busy = true;
+	mod_timer(&intel_crtc->idle_timer, jiffies +
+		  msecs_to_jiffies(CRTC_IDLE_TIMEOUT));
+
 	if (x < 0) {
 		temp |= CURSOR_POS_SIGN << CURSOR_X_SHIFT;
 		x = -x;
@@ -2854,6 +2964,271 @@  struct drm_display_mode *intel_crtc_mode_get(struct drm_device *dev,
 	return mode;
 }
 
+#define GPU_IDLE_TIMEOUT 500 /* ms */
+
+/* When this timer fires, we've been idle for awhile */
+static void intel_gpu_idle_timer(unsigned long arg)
+{
+	struct drm_device *dev = (struct drm_device *)arg;
+	drm_i915_private_t *dev_priv = dev->dev_private;
+
+	DRM_DEBUG("idle timer fired, downclocking\n");
+
+	dev_priv->busy = false;
+
+	schedule_work(&dev_priv->idle_work);
+}
+
+void intel_increase_renderclock(struct drm_device *dev, int schedule)
+{
+	drm_i915_private_t *dev_priv = dev->dev_private;
+
+	if (IS_G4X(dev) || IS_I9XX(dev)) {
+		/* Up to maximum... */
+		pci_write_config_word(dev->pdev, GCFGC, dev_priv->orig_clock);
+	} else if (IS_I85X(dev)) {
+		pci_write_config_word(dev->pdev, HPLLCC, dev_priv->orig_clock);
+	}
+	DRM_DEBUG("increasing render clock frequency\n");
+
+	if (!schedule)
+		return;
+
+	/* Schedule downclock */
+	mod_timer(&dev_priv->idle_timer, jiffies +
+		  msecs_to_jiffies(GPU_IDLE_TIMEOUT));
+}
+
+void intel_decrease_renderclock(struct drm_device *dev)
+{
+	if (IS_G4X(dev)) {
+		u16 gcfgc;
+
+		/* Adjust render clock... */
+		pci_read_config_word(dev->pdev, GCFGC, &gcfgc);
+
+		/* Down to minimum... */
+		gcfgc &= ~GM45_GC_RENDER_CLOCK_MASK;
+		gcfgc |= GM45_GC_RENDER_CLOCK_266_MHZ;
+
+		pci_write_config_word(dev->pdev, GCFGC, gcfgc);
+	} else if (IS_I965G(dev)) {
+		u16 gcfgc;
+
+		/* Adjust render clock... */
+		pci_read_config_word(dev->pdev, GCFGC, &gcfgc);
+
+		/* Down to minimum... */
+		gcfgc &= ~I965_GC_RENDER_CLOCK_MASK;
+		gcfgc |= I965_GC_RENDER_CLOCK_267_MHZ;
+
+		pci_write_config_word(dev->pdev, GCFGC, gcfgc);
+	} else if (IS_I945G(dev) || IS_I945GM(dev)) {
+		u16 gcfgc;
+
+		/* Adjust render clock... */
+		pci_read_config_word(dev->pdev, GCFGC, &gcfgc);
+
+		/* Down to minimum... */
+		gcfgc &= ~I945_GC_RENDER_CLOCK_MASK;
+		gcfgc |= I945_GC_RENDER_CLOCK_166_MHZ;
+
+		pci_write_config_word(dev->pdev, GCFGC, gcfgc);
+	} else if (IS_I915G(dev) || IS_I915GM(dev)) {
+		u16 gcfgc;
+
+		/* Adjust render clock... */
+		pci_read_config_word(dev->pdev, GCFGC, &gcfgc);
+
+		/* Down to minimum... */
+		gcfgc &= ~I915_GC_RENDER_CLOCK_MASK;
+		gcfgc |= I915_GC_RENDER_CLOCK_166_MHZ;
+
+		pci_write_config_word(dev->pdev, GCFGC, gcfgc);
+	} else if (IS_I85X(dev)) {
+		u16 hpllcc;
+
+		/* Adjust render clock... */
+		pci_read_config_word(dev->pdev, HPLLCC, &hpllcc);
+
+		/* Up to maximum... */
+		hpllcc &= ~GC_CLOCK_CONTROL_MASK;
+		hpllcc |= GC_CLOCK_133_200;
+
+		pci_write_config_word(dev->pdev, HPLLCC, hpllcc);
+	}
+	DRM_DEBUG("decreasing render clock frequency\n");
+}
+
+/* Note that no increase function is needed for this - increase_renderclock()
+ *  will also rewrite these bits
+ */
+void intel_decrease_displayclock(struct drm_device *dev)
+{
+	if (IS_I945G(dev) || IS_I945GM(dev) || IS_I915G(dev) ||
+	    IS_I915GM(dev)) {
+		u16 gcfgc;
+
+		/* Adjust render clock... */
+		pci_read_config_word(dev->pdev, GCFGC, &gcfgc);
+
+		/* Down to minimum... */
+		gcfgc &= ~0xf0;
+		gcfgc |= 0x80;
+
+		pci_write_config_word(dev->pdev, GCFGC, gcfgc);
+	}
+}
+
+static void intel_crtc_idle_timer(unsigned long arg)
+{
+	struct intel_crtc *intel_crtc = (struct intel_crtc *)arg;
+	struct drm_crtc *crtc = &intel_crtc->base;
+	drm_i915_private_t *dev_priv = crtc->dev->dev_private;
+
+	DRM_DEBUG("idle timer fired, downclocking\n");
+
+	intel_crtc->busy = false;
+
+	schedule_work(&dev_priv->idle_work);
+}
+
+static void intel_increase_pllclock(struct drm_crtc *crtc, int schedule)
+{
+	struct drm_device *dev = crtc->dev;
+	drm_i915_private_t *dev_priv = dev->dev_private;
+	struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
+	int pipe = intel_crtc->pipe;
+	int dpll_reg = (pipe == 0) ? DPLL_A : DPLL_B;
+	int dpll = I915_READ(dpll_reg);
+
+	if (!HAS_PIPE_CXSR(dev) && (dpll & DISPLAY_RATE_SELECT_FPA1)) {
+		DRM_DEBUG("upclocking LVDS\n");
+
+		I915_WRITE(PP_CONTROL, I915_READ(PP_CONTROL) | (0xabcd << 16));
+		I915_WRITE(dpll_reg, dpll & ~DISPLAY_RATE_SELECT_FPA1);
+		dpll = I915_READ(dpll_reg);
+		intel_wait_for_vblank(dev);
+		dpll = I915_READ(dpll_reg);
+		if (dpll & DISPLAY_RATE_SELECT_FPA1)
+			DRM_DEBUG("failed to upclock LVDS!\n");
+		I915_WRITE(PP_CONTROL, I915_READ(PP_CONTROL) & 0x3);
+	}
+
+	if (!schedule)
+		return;
+
+	/* Schedule downclock */
+	mod_timer(&intel_crtc->idle_timer, jiffies +
+		  msecs_to_jiffies(CRTC_IDLE_TIMEOUT));
+}
+
+static void intel_decrease_pllclock(struct drm_crtc *crtc)
+{
+	struct drm_device *dev = crtc->dev;
+	drm_i915_private_t *dev_priv = dev->dev_private;
+	struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
+	int pipe = intel_crtc->pipe;
+	int dpll_reg = (pipe == 0) ? DPLL_A : DPLL_B;
+	int dpll = I915_READ(dpll_reg);
+
+	/*
+	 * Since this is called by a timer, we should never get here in
+	 * the manual case.
+	 */
+	if (!HAS_PIPE_CXSR(dev) && intel_crtc->lowfreq_avail) {
+		DRM_DEBUG("downclocking LVDS\n");
+		I915_WRITE(PP_CONTROL, I915_READ(PP_CONTROL) | (0xabcd << 16));
+
+		dpll |= DISPLAY_RATE_SELECT_FPA1;
+		I915_WRITE(dpll_reg, dpll);
+		dpll = I915_READ(dpll_reg);
+		intel_wait_for_vblank(dev);
+		dpll = I915_READ(dpll_reg);
+		if (!(dpll & DISPLAY_RATE_SELECT_FPA1))
+			DRM_DEBUG("failed to downclock LVDS!\n");
+		I915_WRITE(PP_CONTROL, I915_READ(PP_CONTROL) & 0x3);
+	}
+
+}
+
+/**
+ * intel_idle_update - adjust clocks for idleness
+ * @work: work struct
+ *
+ * Either the GPU or display (or both) went idle.  Check the busy status
+ * here and adjust the CRTC and GPU clocks as necessary.
+ */
+static void intel_idle_update(struct work_struct *work)
+{
+	drm_i915_private_t *dev_priv = container_of(work, drm_i915_private_t,
+						    idle_work);
+	struct drm_device *dev = dev_priv->dev;
+	struct drm_crtc *crtc;
+	struct intel_crtc *intel_crtc;
+
+	if (!i915_powersave)
+		return;
+
+	mutex_lock(&dev->struct_mutex);
+
+	/* GPU isn't processing, downclock it. */
+	if (!dev_priv->busy) {
+		intel_decrease_renderclock(dev);
+		intel_decrease_displayclock(dev);
+	}
+
+	list_for_each_entry(crtc, &dev->mode_config.crtc_list, head) {
+		/* Skip inactive CRTCs */
+		if (!crtc->fb)
+			continue;
+
+		intel_crtc = to_intel_crtc(crtc);
+		if (!intel_crtc->busy)
+			intel_decrease_pllclock(crtc);
+	}
+
+	mutex_unlock(&dev->struct_mutex);
+}
+
+/**
+ * intel_mark_busy - mark the GPU and possibly the display busy
+ * @dev: drm device
+ * @obj: object we're operating on
+ *
+ * Callers can use this function to indicate that the GPU is busy processing
+ * commands.  If @obj matches one of the CRTC objects (i.e. it's a scanout
+ * buffer), we'll also mark the display as busy, so we know to increase its
+ * clock frequency.
+ */
+void intel_mark_busy(struct drm_device *dev, struct drm_gem_object *obj)
+{
+	drm_i915_private_t *dev_priv = dev->dev_private;
+	struct drm_crtc *crtc = NULL;
+	struct intel_framebuffer *intel_fb;
+	struct intel_crtc *intel_crtc;
+
+	dev_priv->busy = true;
+	intel_increase_renderclock(dev, true);
+
+	list_for_each_entry(crtc, &dev->mode_config.crtc_list, head) {
+		if (!crtc->fb)
+			continue;
+
+		intel_crtc = to_intel_crtc(crtc);
+		intel_fb = to_intel_framebuffer(crtc->fb);
+		if (intel_fb->obj == obj) {
+			if (!intel_crtc->busy)
+				intel_increase_pllclock(crtc, true);
+			intel_crtc->busy = true;
+			mod_timer(&intel_crtc->idle_timer, jiffies +
+				  msecs_to_jiffies(CRTC_IDLE_TIMEOUT));
+		}
+	}
+
+
+}
+
 static void intel_crtc_destroy(struct drm_crtc *crtc)
 {
 	struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
@@ -2909,6 +3284,10 @@  static void intel_crtc_init(struct drm_device *dev, int pipe)
 	intel_crtc->mode_set.crtc = &intel_crtc->base;
 	intel_crtc->mode_set.connectors = (struct drm_connector **)(intel_crtc + 1);
 	intel_crtc->mode_set.num_connectors = 0;
+	intel_crtc->busy = false;
+
+	setup_timer(&intel_crtc->idle_timer, intel_crtc_idle_timer,
+		    (unsigned long)intel_crtc);
 
 	if (i915_fbpercrtc) {
 
@@ -3174,6 +3553,7 @@  static const struct drm_mode_config_funcs intel_mode_funcs = {
 
 void intel_modeset_init(struct drm_device *dev)
 {
+	struct drm_i915_private *dev_priv = dev->dev_private;
 	int num_pipe;
 	int i;
 
@@ -3208,15 +3588,38 @@  void intel_modeset_init(struct drm_device *dev)
 	DRM_DEBUG("%d display pipe%s available.\n",
 		  num_pipe, num_pipe > 1 ? "s" : "");
 
+	if (IS_I85X(dev))
+		pci_read_config_word(dev->pdev, HPLLCC, &dev_priv->orig_clock);
+	else if (IS_I9XX(dev) || IS_G4X(dev))
+		pci_read_config_word(dev->pdev, GCFGC, &dev_priv->orig_clock);
+
 	for (i = 0; i < num_pipe; i++) {
 		intel_crtc_init(dev, i);
 	}
 
 	intel_setup_outputs(dev);
+
+	INIT_WORK(&dev_priv->idle_work, intel_idle_update);
+	setup_timer(&dev_priv->idle_timer, intel_gpu_idle_timer,
+		    (unsigned long)dev);
 }
 
 void intel_modeset_cleanup(struct drm_device *dev)
 {
+	struct drm_i915_private *dev_priv = dev->dev_private;
+
+	/* Clean up up/down clocking */
+	if (!HAS_PIPE_CXSR(dev)) {
+		u32 dpll_b = I915_READ(DPLL_B);
+
+		del_timer_sync(&dev_priv->idle_timer);
+		dpll_b &= ~DISPLAY_RATE_SELECT_FPA1;
+		I915_WRITE(DPLL_B, dpll_b);
+		POSTING_READ(DPLL_B);
+		intel_wait_for_vblank(dev);
+	}
+
+	intel_increase_renderclock(dev, false);
 	drm_mode_config_cleanup(dev);
 }
 
diff --git a/drivers/gpu/drm/i915/intel_drv.h b/drivers/gpu/drm/i915/intel_drv.h
index 004541c..44fe933 100644
--- a/drivers/gpu/drm/i915/intel_drv.h
+++ b/drivers/gpu/drm/i915/intel_drv.h
@@ -98,6 +98,9 @@  struct intel_crtc {
 	struct intel_framebuffer *fbdev_fb;
 	/* a mode_set for fbdev users on this crtc */
 	struct drm_mode_set mode_set;
+	bool busy; /* is scanout buffer being updated frequently? */
+	struct timer_list idle_timer;
+	bool lowfreq_avail;
 };
 
 #define to_intel_crtc(x) container_of(x, struct intel_crtc, base)
@@ -116,6 +119,7 @@  extern void intel_hdmi_init(struct drm_device *dev, int sdvox_reg);
 extern bool intel_sdvo_init(struct drm_device *dev, int output_device);
 extern void intel_dvo_init(struct drm_device *dev);
 extern void intel_tv_init(struct drm_device *dev);
+extern void intel_mark_busy(struct drm_device *dev, struct drm_gem_object *obj);
 extern void intel_lvds_init(struct drm_device *dev);
 extern void intel_dp_init(struct drm_device *dev, int dp_reg);
 void