drm/i915: add FIFO watermark support

This patch from jbarnes and myself adds FIFO watermark control to the
driver.  This is needed for both power saving features on new platforms
with the so-called "big FIFO" and for controlling FIFO allocation
between pipes in multi-head configurations.

It's also necessary infrastructure to support things like framebuffer
compression and configuration supportability checks (i.e. checking a
configuration against available bandwidth).

Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Signed-off-by: Eric Anholt <eric@anholt.net>

5 files changed, 513 insertions, 6 deletions

diff --git a/drivers/gpu/drm/i915/i915_dma.c b/drivers/gpu/drm/i915/i915_dma.c
index f83364974a8a..6096600aff60 100644
--- a/drivers/gpu/drm/i915/i915_dma.c
+++ b/drivers/gpu/drm/i915/i915_dma.c
@@ -1082,6 +1082,44 @@ void i915_master_destroy(struct drm_device *dev, struct drm_master *master)
         master->driver_priv = NULL;
 }
 
+static void i915_get_mem_freq(struct drm_device *dev)
+{
+        drm_i915_private_t *dev_priv = dev->dev_private;
+        u32 tmp;
+
+        if (!IS_IGD(dev))
+                return;
+
+        tmp = I915_READ(CLKCFG);
+
+        switch (tmp & CLKCFG_FSB_MASK) {
+        case CLKCFG_FSB_533:
+                dev_priv->fsb_freq = 533; /* 133*4 */
+                break;
+        case CLKCFG_FSB_800:
+                dev_priv->fsb_freq = 800; /* 200*4 */
+                break;
+        case CLKCFG_FSB_667:
+                dev_priv->fsb_freq =  667; /* 167*4 */
+                break;
+        case CLKCFG_FSB_400:
+                dev_priv->fsb_freq = 400; /* 100*4 */
+                break;
+        }
+
+        switch (tmp & CLKCFG_MEM_MASK) {
+        case CLKCFG_MEM_533:
+                dev_priv->mem_freq = 533;
+                break;
+        case CLKCFG_MEM_667:
+                dev_priv->mem_freq = 667;
+                break;
+        case CLKCFG_MEM_800:
+                dev_priv->mem_freq = 800;
+                break;
+        }
+}
+
 /**
  * i915_driver_load - setup chip and create an initial config
  * @dev: DRM device
@@ -1165,6 +1203,8 @@ int i915_driver_load(struct drm_device *dev, unsigned long flags)
                         goto out_iomapfree;
         }
 
+        i915_get_mem_freq(dev);
+
         /* On the 945G/GM, the chipset reports the MSI capability on the
          * integrated graphics even though the support isn't actually there
          * according to the published specs.  It doesn't appear to function
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index 596e119d3e0e..47ecb617e519 100644
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -225,6 +225,8 @@ typedef struct drm_i915_private {
         int fence_reg_start; /* 4 if userland hasn't ioctl'd us yet */
         int num_fence_regs; /* 8 on pre-965, 16 otherwise */
 
+        unsigned int fsb_freq, mem_freq;
+
         spinlock_t error_lock;
         struct drm_i915_error_state *first_error;
 
@@ -889,6 +891,8 @@ extern int i915_wait_ring(struct drm_device * dev, int n, const char *caller);
 #define SUPPORTS_INTEGRATED_HDMI(dev)   (IS_G4X(dev) || IS_IGDNG(dev))
 #define SUPPORTS_INTEGRATED_DP(dev)     (IS_G4X(dev) || IS_IGDNG(dev))
 #define I915_HAS_HOTPLUG(dev) (IS_I945G(dev) || IS_I945GM(dev) || IS_I965G(dev))
+/* dsparb controlled by hw only */
+#define DSPARB_HWCONTROL(dev) (IS_G4X(dev))
 
 #define PRIMARY_RINGBUFFER_SIZE         (128*1024)
 
diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index 17b308592c4f..7ba23a69a0c0 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -376,11 +376,15 @@ irqreturn_t i915_driver_irq_handler(DRM_IRQ_ARGS)
                  * Clear the PIPE(A|B)STAT regs before the IIR
                  */
                 if (pipea_stats & 0x8000ffff) {
+                        if (pipea_stats &  PIPE_FIFO_UNDERRUN_STATUS)
+                                DRM_DEBUG("pipe a underrun\n");
                         I915_WRITE(PIPEASTAT, pipea_stats);
                         irq_received = 1;
                 }
 
                 if (pipeb_stats & 0x8000ffff) {
+                        if (pipeb_stats &  PIPE_FIFO_UNDERRUN_STATUS)
+                                DRM_DEBUG("pipe b underrun\n");
                         I915_WRITE(PIPEBSTAT, pipeb_stats);
                         irq_received = 1;
                 }
diff --git a/drivers/gpu/drm/i915/i915_reg.h b/drivers/gpu/drm/i915/i915_reg.h
index ad3d1b5db95e..6c0858484094 100644
--- a/drivers/gpu/drm/i915/i915_reg.h
+++ b/drivers/gpu/drm/i915/i915_reg.h
@@ -275,7 +275,13 @@
 #define INSTPM          0x020c0
 #define ACTHD           0x020c8
 #define FW_BLC          0x020d8
+#define FW_BLC2         0x020dc
 #define FW_BLC_SELF     0x020e0 /* 915+ only */
+#define   FW_BLC_SELF_EN (1<<15)
+#define MM_BURST_LENGTH     0x00700000
+#define MM_FIFO_WATERMARK   0x0001F000
+#define LM_BURST_LENGTH     0x00000700
+#define LM_FIFO_WATERMARK   0x0000001F
 #define MI_ARB_STATE    0x020e4 /* 915+ only */
 #define CACHE_MODE_0    0x02120 /* 915+ only */
 #define   CM0_MASK_SHIFT          16
@@ -585,17 +591,21 @@
 
 /* Clocking configuration register */
 #define CLKCFG                  0x10c00
-#define CLKCFG_FSB_400                                  (0 << 0)        /* hrawclk 100 */
+#define CLKCFG_FSB_400                                  (5 << 0)        /* hrawclk 100 */
 #define CLKCFG_FSB_533                                  (1 << 0)        /* hrawclk 133 */
 #define CLKCFG_FSB_667                                  (3 << 0)        /* hrawclk 166 */
 #define CLKCFG_FSB_800                                  (2 << 0)        /* hrawclk 200 */
 #define CLKCFG_FSB_1067                                 (6 << 0)        /* hrawclk 266 */
 #define CLKCFG_FSB_1333                                 (7 << 0)        /* hrawclk 333 */
-/* this is a guess, could be 5 as well */
+/* Note, below two are guess */
 #define CLKCFG_FSB_1600                                 (4 << 0)        /* hrawclk 400 */
-#define CLKCFG_FSB_1600_ALT                             (5 << 0)        /* hrawclk 400 */
+#define CLKCFG_FSB_1600_ALT                             (0 << 0)        /* hrawclk 400 */
 #define CLKCFG_FSB_MASK                                 (7 << 0)
- 
+#define CLKCFG_MEM_533                                  (1 << 4)
+#define CLKCFG_MEM_667                                  (2 << 4)
+#define CLKCFG_MEM_800                                  (3 << 4)
+#define CLKCFG_MEM_MASK                                 (7 << 4)
+
 /** GM965 GM45 render standby register */
 #define MCHBAR_RENDER_STANDBY   0x111B8
 
@@ -1595,6 +1605,34 @@
 #define   DSPARB_CSTART_SHIFT   7
 #define   DSPARB_BSTART_MASK    (0x7f)
 #define   DSPARB_BSTART_SHIFT   0
+#define   DSPARB_BEND_SHIFT     9 /* on 855 */
+#define   DSPARB_AEND_SHIFT     0
+
+#define DSPFW1                  0x70034
+#define DSPFW2                  0x70038
+#define DSPFW3                  0x7003c
+#define   IGD_SELF_REFRESH_EN   (1<<30)
+
+/* FIFO watermark sizes etc */
+#define I915_FIFO_LINE_SIZE     64
+#define I830_FIFO_LINE_SIZE     32
+#define I945_FIFO_SIZE          127 /* 945 & 965 */
+#define I915_FIFO_SIZE          95
+#define I855GM_FIFO_SIZE        255
+#define I830_FIFO_SIZE          95
+#define I915_MAX_WM             0x3f
+
+#define IGD_DISPLAY_FIFO        512 /* in 64byte unit */
+#define IGD_FIFO_LINE_SIZE      64
+#define IGD_MAX_WM              0x1ff
+#define IGD_DFT_WM              0x3f
+#define IGD_DFT_HPLLOFF_WM      0
+#define IGD_GUARD_WM            10
+#define IGD_CURSOR_FIFO         64
+#define IGD_CURSOR_MAX_WM       0x3f
+#define IGD_CURSOR_DFT_WM       0
+#define IGD_CURSOR_GUARD_WM     5
+
 /*
  * The two pipe frame counter registers are not synchronized, so
  * reading a stable value is somewhat tricky. The following code
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 73e7b9cecac8..a84ac05ef048 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -25,6 +25,7 @@
  */
 
 #include <linux/i2c.h>
+#include <linux/kernel.h>
 #include "drmP.h"
 #include "intel_drv.h"
 #include "i915_drm.h"
@@ -34,6 +35,7 @@
 #include "drm_crtc_helper.h"
 
 bool intel_pipe_has_type (struct drm_crtc *crtc, int type);
+static void intel_update_watermarks(struct drm_device *dev);
 
 typedef struct {
     /* given values */
@@ -1005,7 +1007,7 @@ static void igdng_crtc_dpms(struct drm_crtc *crtc, int mode)
         struct drm_i915_private *dev_priv = dev->dev_private;
         struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
         int pipe = intel_crtc->pipe;
-        int plane = intel_crtc->pipe;
+        int plane = intel_crtc->plane;
         int pch_dpll_reg = (pipe == 0) ? PCH_DPLL_A : PCH_DPLL_B;
         int pipeconf_reg = (pipe == 0) ? PIPEACONF : PIPEBCONF;
         int dspcntr_reg = (plane == 0) ? DSPACNTR : DSPBCNTR;
@@ -1335,8 +1337,10 @@ static void i9xx_crtc_dpms(struct drm_crtc *crtc, int mode)
 
                 /* Give the overlay scaler a chance to enable if it's on this pipe */
                 //intel_crtc_dpms_video(crtc, true); TODO
+                intel_update_watermarks(dev);
         break;
         case DRM_MODE_DPMS_OFF:
+                intel_update_watermarks(dev);
                 /* Give the overlay scaler a chance to disable if it's on this pipe */
                 //intel_crtc_dpms_video(crtc, FALSE); TODO
 
@@ -1515,7 +1519,6 @@ static int intel_get_core_clock_speed(struct drm_device *dev)
         return 0; /* Silence gcc warning */
 }
 
-
 /**
  * Return the pipe currently connected to the panel fitter,
  * or -1 if the panel fitter is not present or not in use
@@ -1585,6 +1588,420 @@ igdng_compute_m_n(int bytes_per_pixel, int nlanes,
 }
 
 
+struct intel_watermark_params {
+        unsigned long fifo_size;
+        unsigned long max_wm;
+        unsigned long default_wm;
+        unsigned long guard_size;
+        unsigned long cacheline_size;
+};
+
+/* IGD has different values for various configs */
+static struct intel_watermark_params igd_display_wm = {
+        IGD_DISPLAY_FIFO,
+        IGD_MAX_WM,
+        IGD_DFT_WM,
+        IGD_GUARD_WM,
+        IGD_FIFO_LINE_SIZE
+};
+static struct intel_watermark_params igd_display_hplloff_wm = {
+        IGD_DISPLAY_FIFO,
+        IGD_MAX_WM,
+        IGD_DFT_HPLLOFF_WM,
+        IGD_GUARD_WM,
+        IGD_FIFO_LINE_SIZE
+};
+static struct intel_watermark_params igd_cursor_wm = {
+        IGD_CURSOR_FIFO,
+        IGD_CURSOR_MAX_WM,
+        IGD_CURSOR_DFT_WM,
+        IGD_CURSOR_GUARD_WM,
+        IGD_FIFO_LINE_SIZE,
+};
+static struct intel_watermark_params igd_cursor_hplloff_wm = {
+        IGD_CURSOR_FIFO,
+        IGD_CURSOR_MAX_WM,
+        IGD_CURSOR_DFT_WM,
+        IGD_CURSOR_GUARD_WM,
+        IGD_FIFO_LINE_SIZE
+};
+static struct intel_watermark_params i945_wm_info = {
+        I915_FIFO_LINE_SIZE,
+        I915_MAX_WM,
+        1,
+        0,
+        IGD_FIFO_LINE_SIZE
+};
+static struct intel_watermark_params i915_wm_info = {
+        I945_FIFO_SIZE,
+        I915_MAX_WM,
+        1,
+        0,
+        I915_FIFO_LINE_SIZE
+};
+static struct intel_watermark_params i855_wm_info = {
+        I855GM_FIFO_SIZE,
+        I915_MAX_WM,
+        1,
+        0,
+        I830_FIFO_LINE_SIZE
+};
+static struct intel_watermark_params i830_wm_info = {
+        I830_FIFO_SIZE,
+        I915_MAX_WM,
+        1,
+        0,
+        I830_FIFO_LINE_SIZE
+};
+
+static unsigned long intel_calculate_wm(unsigned long clock_in_khz,
+                                        struct intel_watermark_params *wm,
+                                        int pixel_size,
+                                        unsigned long latency_ns)
+{
+        unsigned long bytes_required, wm_size;
+
+        bytes_required = (clock_in_khz * pixel_size * latency_ns) / 1000000;
+        bytes_required /= wm->cacheline_size;
+        wm_size = wm->fifo_size - bytes_required - wm->guard_size;
+
+        if (wm_size > wm->max_wm)
+                wm_size = wm->max_wm;
+        if (wm_size == 0)
+                wm_size = wm->default_wm;
+        return wm_size;
+}
+
+struct cxsr_latency {
+        int is_desktop;
+        unsigned long fsb_freq;
+        unsigned long mem_freq;
+        unsigned long display_sr;
+        unsigned long display_hpll_disable;
+        unsigned long cursor_sr;
+        unsigned long cursor_hpll_disable;
+};
+
+static struct cxsr_latency cxsr_latency_table[] = {
+        {1, 800, 400, 3382, 33382, 3983, 33983},    /* DDR2-400 SC */
+        {1, 800, 667, 3354, 33354, 3807, 33807},    /* DDR2-667 SC */
+        {1, 800, 800, 3347, 33347, 3763, 33763},    /* DDR2-800 SC */
+
+        {1, 667, 400, 3400, 33400, 4021, 34021},    /* DDR2-400 SC */
+        {1, 667, 667, 3372, 33372, 3845, 33845},    /* DDR2-667 SC */
+        {1, 667, 800, 3386, 33386, 3822, 33822},    /* DDR2-800 SC */
+
+        {1, 400, 400, 3472, 33472, 4173, 34173},    /* DDR2-400 SC */
+        {1, 400, 667, 3443, 33443, 3996, 33996},    /* DDR2-667 SC */
+        {1, 400, 800, 3430, 33430, 3946, 33946},    /* DDR2-800 SC */
+
+        {0, 800, 400, 3438, 33438, 4065, 34065},    /* DDR2-400 SC */
+        {0, 800, 667, 3410, 33410, 3889, 33889},    /* DDR2-667 SC */
+        {0, 800, 800, 3403, 33403, 3845, 33845},    /* DDR2-800 SC */
+
+        {0, 667, 400, 3456, 33456, 4103, 34106},    /* DDR2-400 SC */
+        {0, 667, 667, 3428, 33428, 3927, 33927},    /* DDR2-667 SC */
+        {0, 667, 800, 3443, 33443, 3905, 33905},    /* DDR2-800 SC */
+
+        {0, 400, 400, 3528, 33528, 4255, 34255},    /* DDR2-400 SC */
+        {0, 400, 667, 3500, 33500, 4079, 34079},    /* DDR2-667 SC */
+        {0, 400, 800, 3487, 33487, 4029, 34029},    /* DDR2-800 SC */
+};
+
+static struct cxsr_latency *intel_get_cxsr_latency(int is_desktop, int fsb,
+                                                   int mem)
+{
+        int i;
+        struct cxsr_latency *latency;
+
+        if (fsb == 0 || mem == 0)
+                return NULL;
+
+        for (i = 0; i < ARRAY_SIZE(cxsr_latency_table); i++) {
+                latency = &cxsr_latency_table[i];
+                if (is_desktop == latency->is_desktop &&
+                        fsb == latency->fsb_freq && mem == latency->mem_freq)
+                        break;
+        }
+        if (i >= ARRAY_SIZE(cxsr_latency_table)) {
+                DRM_DEBUG("Unknown FSB/MEM found, disable CxSR\n");
+                return NULL;
+        }
+        return latency;
+}
+
+static void igd_disable_cxsr(struct drm_device *dev)
+{
+        struct drm_i915_private *dev_priv = dev->dev_private;
+        u32 reg;
+
+        /* deactivate cxsr */
+        reg = I915_READ(DSPFW3);
+        reg &= ~(IGD_SELF_REFRESH_EN);
+        I915_WRITE(DSPFW3, reg);
+        DRM_INFO("Big FIFO is disabled\n");
+}
+
+static void igd_enable_cxsr(struct drm_device *dev, unsigned long clock,
+                            int pixel_size)
+{
+        struct drm_i915_private *dev_priv = dev->dev_private;
+        u32 reg;
+        unsigned long wm;
+        struct cxsr_latency *latency;
+
+        latency = intel_get_cxsr_latency(IS_IGDG(dev), dev_priv->fsb_freq,
+                dev_priv->mem_freq);
+        if (!latency) {
+                DRM_DEBUG("Unknown FSB/MEM found, disable CxSR\n");
+                igd_disable_cxsr(dev);
+                return;
+        }
+
+        /* Display SR */
+        wm = intel_calculate_wm(clock, &igd_display_wm, pixel_size,
+                                latency->display_sr);
+        reg = I915_READ(DSPFW1);
+        reg &= 0x7fffff;
+        reg |= wm << 23;
+        I915_WRITE(DSPFW1, reg);
+        DRM_DEBUG("DSPFW1 register is %x\n", reg);
+
+        /* cursor SR */
+        wm = intel_calculate_wm(clock, &igd_cursor_wm, pixel_size,
+                                latency->cursor_sr);
+        reg = I915_READ(DSPFW3);
+        reg &= ~(0x3f << 24);
+        reg |= (wm & 0x3f) << 24;
+        I915_WRITE(DSPFW3, reg);
+
+        /* Display HPLL off SR */
+        wm = intel_calculate_wm(clock, &igd_display_hplloff_wm,
+                latency->display_hpll_disable, I915_FIFO_LINE_SIZE);
+        reg = I915_READ(DSPFW3);
+        reg &= 0xfffffe00;
+        reg |= wm & 0x1ff;
+        I915_WRITE(DSPFW3, reg);
+
+        /* cursor HPLL off SR */
+        wm = intel_calculate_wm(clock, &igd_cursor_hplloff_wm, pixel_size,
+                                latency->cursor_hpll_disable);
+        reg = I915_READ(DSPFW3);
+        reg &= ~(0x3f << 16);
+        reg |= (wm & 0x3f) << 16;
+        I915_WRITE(DSPFW3, reg);
+        DRM_DEBUG("DSPFW3 register is %x\n", reg);
+
+        /* activate cxsr */
+        reg = I915_READ(DSPFW3);
+        reg |= IGD_SELF_REFRESH_EN;
+        I915_WRITE(DSPFW3, reg);
+
+        DRM_INFO("Big FIFO is enabled\n");
+
+        return;
+}
+
+const static int latency_ns = 5000; /* default for non-igd platforms */
+
+
+static void i965_update_wm(struct drm_device *dev)
+{
+        struct drm_i915_private *dev_priv = dev->dev_private;
+
+        DRM_DEBUG("Setting FIFO watermarks - A: 8, B: 8, C: 8, SR 8\n");
+
+        /* 965 has limitations... */
+        I915_WRITE(DSPFW1, (8 << 16) | (8 << 8) | (8 << 0));
+        I915_WRITE(DSPFW2, (8 << 8) | (8 << 0));
+}
+
+static void i9xx_update_wm(struct drm_device *dev, int planea_clock,
+                           int planeb_clock, int sr_hdisplay, int pixel_size)
+{
+        struct drm_i915_private *dev_priv = dev->dev_private;
+        uint32_t fwater_lo = I915_READ(FW_BLC) & MM_FIFO_WATERMARK;
+        uint32_t fwater_hi = I915_READ(FW_BLC2) & LM_FIFO_WATERMARK;
+        int bsize, asize, cwm, bwm = 1, awm = 1, srwm = 1;
+        uint32_t dsparb = I915_READ(DSPARB);
+        int planea_entries, planeb_entries;
+        struct intel_watermark_params *wm_params;
+        unsigned long line_time_us;
+        int sr_clock, sr_entries = 0;
+
+        if (IS_I965GM(dev) || IS_I945GM(dev))
+                wm_params = &i945_wm_info;
+        else if (IS_I9XX(dev))
+                wm_params = &i915_wm_info;
+        else
+                wm_params = &i855_wm_info;
+
+        planea_entries = intel_calculate_wm(planea_clock, wm_params,
+                                            pixel_size, latency_ns);
+        planeb_entries = intel_calculate_wm(planeb_clock, wm_params,
+                                            pixel_size, latency_ns);
+
+        DRM_DEBUG("FIFO entries - A: %d, B: %d\n", planea_entries,
+                  planeb_entries);
+
+        if (IS_I9XX(dev)) {
+                asize = dsparb & 0x7f;
+                bsize = (dsparb >> DSPARB_CSTART_SHIFT) & 0x7f;
+        } else {
+                asize = dsparb & 0x1ff;
+                bsize = (dsparb >> DSPARB_BEND_SHIFT) & 0x1ff;
+        }
+        DRM_DEBUG("FIFO size - A: %d, B: %d\n", asize, bsize);
+
+        /* Two extra entries for padding */
+        awm = asize - (planea_entries + 2);
+        bwm = bsize - (planeb_entries + 2);
+
+        /* Sanity check against potentially bad FIFO allocations */
+        if (awm <= 0) {
+                /* pipe is on but has too few FIFO entries */
+                if (planea_entries != 0)
+                        DRM_DEBUG("plane A needs more FIFO entries\n");
+                awm = 1;
+        }
+        if (bwm <= 0) {
+                if (planeb_entries != 0)
+                        DRM_DEBUG("plane B needs more FIFO entries\n");
+                bwm = 1;
+        }
+
+        /*
+         * Overlay gets an aggressive default since video jitter is bad.
+         */
+        cwm = 2;
+
+        /* Calc sr entries for one pipe configs */
+        if (!planea_clock || !planeb_clock) {
+                sr_clock = planea_clock ? planea_clock : planeb_clock;
+                line_time_us = (sr_hdisplay * 1000) / sr_clock;
+                sr_entries = (((latency_ns / line_time_us) + 1) * pixel_size *
+                              sr_hdisplay) / 1000;
+                sr_entries = roundup(sr_entries / wm_params->cacheline_size, 1);
+                if (sr_entries < wm_params->fifo_size)
+                        srwm = wm_params->fifo_size - sr_entries;
+        }
+
+        DRM_DEBUG("Setting FIFO watermarks - A: %d, B: %d, C: %d, SR %d\n",
+                  awm, bwm, cwm, srwm);
+
+        fwater_lo = fwater_lo | ((bwm & 0x3f) << 16) | (awm & 0x3f);
+        fwater_hi = fwater_hi | (cwm & 0x1f);
+
+        I915_WRITE(FW_BLC, fwater_lo);
+        I915_WRITE(FW_BLC2, fwater_hi);
+        if (IS_I9XX(dev))
+                I915_WRITE(FW_BLC_SELF, FW_BLC_SELF_EN | (srwm & 0x3f));
+}
+
+static void i830_update_wm(struct drm_device *dev, int planea_clock,
+                           int pixel_size)
+{
+        struct drm_i915_private *dev_priv = dev->dev_private;
+        uint32_t dsparb = I915_READ(DSPARB);
+        uint32_t fwater_lo = I915_READ(FW_BLC) & MM_FIFO_WATERMARK;
+        unsigned int asize, awm;
+        int planea_entries;
+
+        planea_entries = intel_calculate_wm(planea_clock, &i830_wm_info,
+                                            pixel_size, latency_ns);
+
+        asize = dsparb & 0x7f;
+
+        awm = asize - planea_entries;
+
+        fwater_lo = fwater_lo | awm;
+
+        I915_WRITE(FW_BLC, fwater_lo);
+}
+
+/**
+ * intel_update_watermarks - update FIFO watermark values based on current modes
+ *
+ * Calculate watermark values for the various WM regs based on current mode
+ * and plane configuration.
+ *
+ * There are several cases to deal with here:
+ *   - normal (i.e. non-self-refresh)
+ *   - self-refresh (SR) mode
+ *   - lines are large relative to FIFO size (buffer can hold up to 2)
+ *   - lines are small relative to FIFO size (buffer can hold more than 2
+ *     lines), so need to account for TLB latency
+ *
+ *   The normal calculation is:
+ *     watermark = dotclock * bytes per pixel * latency
+ *   where latency is platform & configuration dependent (we assume pessimal
+ *   values here).
+ *
+ *   The SR calculation is:
+ *     watermark = (trunc(latency/line time)+1) * surface width *
+ *       bytes per pixel
+ *   where
+ *     line time = htotal / dotclock
+ *   and latency is assumed to be high, as above.
+ *
+ * The final value programmed to the register should always be rounded up,
+ * and include an extra 2 entries to account for clock crossings.
+ *
+ * We don't use the sprite, so we can ignore that.  And on Crestline we have
+ * to set the non-SR watermarks to 8.
+  */
+static void intel_update_watermarks(struct drm_device *dev)
+{
+        struct drm_crtc *crtc;
+        struct intel_crtc *intel_crtc;
+        int sr_hdisplay = 0;
+        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);
+                if (crtc->enabled) {
+                        enabled++;
+                        if (intel_crtc->plane == 0) {
+                                DRM_DEBUG("plane A (pipe %d) clock: %d\n",
+                                          intel_crtc->pipe, crtc->mode.clock);
+                                planea_clock = crtc->mode.clock;
+                        } else {
+                                DRM_DEBUG("plane B (pipe %d) clock: %d\n",
+                                          intel_crtc->pipe, crtc->mode.clock);
+                                planeb_clock = crtc->mode.clock;
+                        }
+                        sr_hdisplay = crtc->mode.hdisplay;
+                        sr_clock = crtc->mode.clock;
+                        if (crtc->fb)
+                                pixel_size = crtc->fb->bits_per_pixel / 8;
+                        else
+                                pixel_size = 4; /* by default */
+                }
+        }
+
+        if (enabled <= 0)
+                return;
+
+        /* Single pipe configs can enable self refresh */
+        if (enabled == 1 && IS_IGD(dev))
+                igd_enable_cxsr(dev, sr_clock, pixel_size);
+        else if (IS_IGD(dev))
+                igd_disable_cxsr(dev);
+
+        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,
+                               pixel_size);
+        else
+                i830_update_wm(dev, planea_clock, pixel_size);
+}
+
 static int intel_crtc_mode_set(struct drm_crtc *crtc,
                                struct drm_display_mode *mode,
                                struct drm_display_mode *adjusted_mode,
@@ -1951,6 +2368,9 @@ static int intel_crtc_mode_set(struct drm_crtc *crtc,
 
         /* Flush the plane changes */
         ret = intel_pipe_set_base(crtc, x, y, old_fb);
+
+        intel_update_watermarks(dev);
+
         drm_vblank_post_modeset(dev, pipe);
 
         return ret;
@@ -2439,6 +2859,7 @@ static void intel_crtc_init(struct drm_device *dev, int pipe)
 
         drm_mode_crtc_set_gamma_size(&intel_crtc->base, 256);
         intel_crtc->pipe = pipe;
+        intel_crtc->plane = pipe;
         for (i = 0; i < 256; i++) {
                 intel_crtc->lut_r[i] = i;
                 intel_crtc->lut_g[i] = i;