port over ironlake fdi/dpms code from 2.6.34 kernel

(cherry picked from commit 00e824b7cd59000e118dad55f563823b65148e01)

Conflicts:

	src/i830_display.c
	src/i830_lvds.c

from RHEL5 ironlake branch, courtesy of airlied.

2 files changed, 201 insertions, 191 deletions

diff --git a/src/i830_display.c b/src/i830_display.c
index bdf0191e..fa2d94e8 100644
--- a/src/i830_display.c
+++ b/src/i830_display.c
@@ -1487,6 +1487,100 @@ i830_crtc_disable(xf86CrtcPtr crtc, Bool disable_pipe)
     i830_disable_vga_plane (crtc);
 }
 
+static void ironlake_fdi_link_train(xf86CrtcPtr crtc)
+{
+    ScrnInfoPtr scrn = crtc->scrn;
+    intel_screen_private *intel = intel_get_screen_private(scrn);
+    xf86CrtcConfigPtr xf86_config = XF86_CRTC_CONFIG_PTR(scrn);
+    I830CrtcPrivatePtr intel_crtc = crtc->driver_private;
+    int pipe = intel_crtc->pipe;
+    int fdi_tx_reg = (pipe == 0) ? FDI_TXA_CTL : FDI_TXB_CTL;
+    int fdi_rx_reg = (pipe == 0) ? FDI_RXA_CTL : FDI_RXB_CTL;
+    int fdi_rx_iir_reg = (pipe == 0) ? FDI_RXA_IIR : FDI_RXB_IIR;
+    int fdi_rx_imr_reg = (pipe == 0) ? FDI_RXA_IMR : FDI_RXB_IMR;
+    uint32_t temp, tries = 0;
+    
+    /* enable CPU FDI TX and PCH FDI RX */
+    temp = INREG(fdi_tx_reg);
+    temp |= FDI_TX_ENABLE;
+    temp &= ~(7 << 19);
+    temp |= /*(intel_crtc->fdi_lanes - 1)*/3 << 19;
+    temp &= ~FDI_LINK_TRAIN_NONE;
+    temp |= FDI_LINK_TRAIN_PATTERN_1;
+    OUTREG(fdi_tx_reg, temp);
+    INREG(fdi_tx_reg);
+    
+    temp = INREG(fdi_rx_reg);
+    temp &= ~FDI_LINK_TRAIN_NONE;
+    temp |= FDI_LINK_TRAIN_PATTERN_1;
+    OUTREG(fdi_rx_reg, temp | FDI_RX_ENABLE);
+    INREG(fdi_rx_reg);
+    usleep(150);
+    
+    /* Train 1: umask FDI RX Interrupt symbol_lock and bit_lock bit
+       for train result */
+    temp = INREG(fdi_rx_imr_reg);
+    temp &= ~FDI_RX_SYMBOL_LOCK;
+    temp &= ~FDI_RX_BIT_LOCK;
+    OUTREG(fdi_rx_imr_reg, temp);
+    INREG(fdi_rx_imr_reg);
+    usleep(150);
+
+    for (;;) {
+	temp = INREG(fdi_rx_iir_reg);
+	ErrorF("FDI_RX_IIR 0x%x\n", temp);
+	
+	if ((temp & FDI_RX_BIT_LOCK)) {
+	    ErrorF("FDI train 1 done.\n");
+	    OUTREG(fdi_rx_iir_reg,
+		       temp | FDI_RX_BIT_LOCK);
+	    break;
+	}
+	
+	tries++;
+
+	if (tries > 5) {
+	    ErrorF("FDI train 1 fail!\n");
+	    break;
+	}
+    }
+    
+    /* Train 2 */
+    temp = INREG(fdi_tx_reg);
+    temp &= ~FDI_LINK_TRAIN_NONE;
+    temp |= FDI_LINK_TRAIN_PATTERN_2;
+    OUTREG(fdi_tx_reg, temp);
+
+    temp = INREG(fdi_rx_reg);
+    temp &= ~FDI_LINK_TRAIN_NONE;
+    temp |= FDI_LINK_TRAIN_PATTERN_2;
+    OUTREG(fdi_rx_reg, temp);
+    usleep(150);
+
+    tries = 0;
+
+    for (;;) {
+	temp = INREG(fdi_rx_iir_reg);
+	ErrorF("FDI_RX_IIR 0x%x\n", temp);
+	
+	if (temp & FDI_RX_SYMBOL_LOCK) {
+	    OUTREG(fdi_rx_iir_reg,
+		       temp | FDI_RX_SYMBOL_LOCK);
+	    ErrorF("FDI train 2 done.\n");
+	    break;
+	}
+
+	tries++;
+
+	if (tries > 5) {
+	    ErrorF("FDI train 2 fail!\n");
+	    break;
+	}
+    }
+    
+    ErrorF("FDI train done\n");
+}
+
 static void igdng_crtc_dpms(xf86CrtcPtr crtc, int mode)
 {
     ScrnInfoPtr scrn = crtc->scrn;
@@ -1538,38 +1632,35 @@ static void igdng_crtc_dpms(xf86CrtcPtr crtc, int mode)
     case DPMSModeSuspend:
 
 	/* XXX no LVDS port force */
-
-	ErrorF("PCH DPLL enable\n");
-	/* enable PCH DPLL */
-	while (!((temp = INREG(pch_dpll_reg)) & DPLL_VCO_ENABLE)) {
-	    OUTREG(pch_dpll_reg, temp | DPLL_VCO_ENABLE);
-	    INREG(pch_dpll_reg);
-	    usleep(10);
+	if (i830PipeHasType(crtc, I830_OUTPUT_LVDS)) {
+	    temp = INREG(PCH_LVDS);
+	    if ((temp & LVDS_PORT_EN) == 0) {
+		OUTREG(PCH_LVDS, temp | LVDS_PORT_EN);
+		INREG(PCH_LVDS);
+	    }
 	}
 
 	ErrorF("PCH FDI RX PLL enable\n");
 	temp = INREG(fdi_rx_reg);
-	
 	temp &= ~(0x7 << 16);
 	temp |= (pipe_bpc << 11);
-	temp &= ~(FDI_DP_PORT_WIDTH_MASK << 19);
+	temp &= ~(FDI_DP_PORT_WIDTH_MASK);
 	temp |= FDI_DP_PORT_WIDTH_X4;
 
-	OUTREG(fdi_rx_reg, temp); /* default 4 lanes */
+	OUTREG(fdi_rx_reg, temp | FDI_RX_PLL_ENABLE); /* default 4 lanes */
 	INREG(fdi_rx_reg);
 	usleep(200);
 
 	temp = INREG(fdi_rx_reg);
 	OUTREG(fdi_rx_reg, temp | FDI_SEL_PCDCLK); 
-	INREG(fdi_rx_reg);
+	temp = INREG(fdi_rx_reg);
 	usleep(200);
 
-	ErrorF("PCH FDI TX PLL enable\n");
- 	/* Enable CPU FDI TX PLL, always on for IGDNG */
- 	while (!((temp = INREG(fdi_tx_reg)) & FDI_TX_PLL_ENABLE)) {
- 	    temp &= (~FDI_DP_PORT_WIDTH_MASK);
-	    temp |= FDI_TX_PLL_ENABLE | FDI_DP_PORT_WIDTH_X4;
-	    OUTREG(fdi_tx_reg, temp);
+	ErrorF("PCH FDI TX PLL enable %08x\n", temp);
+	temp = INREG(fdi_tx_reg);
+	if ((temp & FDI_TX_PLL_ENABLE) == 0) {
+	    OUTREG(fdi_tx_reg, temp | FDI_TX_PLL_ENABLE);
+	    INREG(fdi_tx_reg);
 	    usleep(100);
 	}
 
@@ -1589,7 +1680,8 @@ static void igdng_crtc_dpms(xf86CrtcPtr crtc, int mode)
 
 	ErrorF("Pipe enable\n");
 	/* Enable CPU pipe */
-	while (!((temp = INREG(pipeconf_reg)) & PIPEACONF_ENABLE)) {
+	temp = INREG(pipeconf_reg);
+	if ((temp & PIPEACONF_ENABLE) == 0) {
 	    OUTREG(pipeconf_reg, temp | PIPEACONF_ENABLE);
 	    INREG(pipeconf_reg);
 	    usleep(100);
@@ -1597,7 +1689,8 @@ static void igdng_crtc_dpms(xf86CrtcPtr crtc, int mode)
 
 	ErrorF("Plane enable\n");
 	/* configure and enable CPU plane */
-	while (!((temp = INREG(dspcntr_reg)) & DISPLAY_PLANE_ENABLE)) {
+	temp = INREG(dspcntr_reg);
+	if ((temp & DISPLAY_PLANE_ENABLE) == 0) {
 	    OUTREG(dspcntr_reg, temp | DISPLAY_PLANE_ENABLE);
 	    /* Flush the plane changes */
 	    OUTREG(dspbase_reg, INREG(dspbase_reg));
@@ -1607,80 +1700,16 @@ static void igdng_crtc_dpms(xf86CrtcPtr crtc, int mode)
 	OUTREG(dspcntr_reg, temp | DISPLAY_PLANE_ENABLE);
 
 	/* Train FDI. */
+	ironlake_fdi_link_train(crtc);
 
-	ErrorF("FDI TX enable\n");
-	/* enable CPU FDI TX and PCH FDI RX */
-	while (!((temp = INREG(fdi_tx_reg)) & FDI_TX_ENABLE)) {
-	    temp |= FDI_TX_ENABLE;
-	    temp |= FDI_DP_PORT_WIDTH_X4; /* default */
-	    temp &= ~FDI_LINK_TRAIN_NONE;
-	    temp |= FDI_LINK_TRAIN_PATTERN_1;
-	    OUTREG(fdi_tx_reg, temp);
-	    usleep(10);
-	}
-
-	ErrorF("FDI RX enable\n");
-	while (!((temp = INREG(fdi_rx_reg)) & FDI_RX_ENABLE)) {
-	    temp &= ~FDI_LINK_TRAIN_NONE;
-	    temp |= FDI_LINK_TRAIN_PATTERN_1;
-	    OUTREG(fdi_rx_reg, temp | FDI_RX_ENABLE);
-	    usleep(10);
-	}
-
-	usleep(150);
-
-	ErrorF("FDI link train 1 start\n");
-	/* unmask FDI RX Interrupt symbol_lock and bit_lock bit
-	   for train result */
-	while ((temp = INREG(fdi_rx_imr_reg)) &
-	       (FDI_RX_SYMBOL_LOCK|FDI_RX_BIT_LOCK)) {
-	    temp &= ~(FDI_RX_SYMBOL_LOCK | FDI_RX_BIT_LOCK);
-	    OUTREG(fdi_rx_imr_reg, temp);
-	    usleep(150);
-	}
-
-
-	ErrorF("FDI link train 1 wait\n");
-	for (j = 0; j < tries; j++) {
-	    temp = INREG(fdi_rx_iir_reg);
-	    if (temp & FDI_RX_BIT_LOCK)
-		break;
-	    usleep(200);
-	}
-	if (j == tries)
-		xf86DrvMsg(scrn->scrnIndex, X_WARNING, "train 1 failed\n");
-
-	ErrorF("FDI link train 2 start TX\n");
-	while (!((temp = INREG(fdi_tx_reg)) & FDI_LINK_TRAIN_PATTERN_2)) {
-	    temp &= ~FDI_LINK_TRAIN_NONE;
-	    temp |= FDI_LINK_TRAIN_PATTERN_2;
-	    OUTREG(fdi_tx_reg, temp);
-	    usleep(10);
-	}
-
-	ErrorF("FDI link train 2 start TX\n");
-	while (!((temp = INREG(fdi_rx_reg)) & FDI_LINK_TRAIN_PATTERN_2)) {
-	    temp &= ~FDI_LINK_TRAIN_NONE;
-	    temp |= FDI_LINK_TRAIN_PATTERN_2;
-	    OUTREG(fdi_rx_reg, temp);
-	    usleep(10);
+	/* enable PCH DPLL */
+	temp = INREG(pch_dpll_reg);
+	if ((temp & DPLL_VCO_ENABLE) == 0) {
+	    OUTREG(pch_dpll_reg, temp | DPLL_VCO_ENABLE);
+	    INREG(pch_dpll_reg);
 	}
+	usleep(200);
 
-	usleep(500);
-
-	ErrorF("FDI link train 2 wait\n");
-	for (j = 0; j < tries; j++) {
-	    temp = INREG(fdi_rx_iir_reg);
-	    if (temp & FDI_RX_SYMBOL_LOCK)
-		break;
-	    usleep(200);
- 	}
-	if (j == tries)
-	    xf86DrvMsg(scrn->scrnIndex, X_WARNING, "train 2 failed\n");
-
-	usleep(500);
-
-	ErrorF("transcoder timing\n");
 	/* set transcoder timing */
 	OUTREG(trans_htot_reg, INREG(cpu_htot_reg));
 	OUTREG(trans_hblank_reg, INREG(cpu_hblank_reg));
@@ -1693,41 +1722,31 @@ static void igdng_crtc_dpms(xf86CrtcPtr crtc, int mode)
 	/* enable normal */
 
 	ErrorF("FDI TX link normal\n");
-	while (((temp = INREG(fdi_tx_reg)) & FDI_LINK_TRAIN_NONE) != FDI_LINK_TRAIN_NONE) {
-	    temp &= ~FDI_LINK_TRAIN_NONE;
-	    OUTREG(fdi_tx_reg, temp | FDI_LINK_TRAIN_NONE |
-		       FDI_TX_ENHANCE_FRAME_ENABLE);
-	    usleep(10);
-	}
+	temp = INREG(fdi_tx_reg);
+	temp &= ~FDI_LINK_TRAIN_NONE;
+	OUTREG(fdi_tx_reg, temp | FDI_LINK_TRAIN_NONE |
+		   FDI_TX_ENHANCE_FRAME_ENABLE);
+	INREG(fdi_tx_reg);
 
-	ErrorF("FDI RX link normal\n");
-	while (((temp = INREG(fdi_rx_reg)) & FDI_LINK_TRAIN_NONE) != FDI_LINK_TRAIN_NONE) {
-	    temp &= ~FDI_LINK_TRAIN_NONE;
-	    OUTREG(fdi_rx_reg, temp | FDI_LINK_TRAIN_NONE |
-		       FDI_RX_ENHANCE_FRAME_ENABLE);
-	    usleep(10);
-	}
+	temp = INREG(fdi_rx_reg);
+	temp &= ~FDI_LINK_TRAIN_NONE;
+	temp |= FDI_LINK_TRAIN_NONE;
+	
+	OUTREG(fdi_rx_reg, temp | FDI_LINK_TRAIN_NONE);
+	INREG(fdi_rx_reg);
 
-	usleep(500);
+	usleep(100);
 
 	ErrorF("transcoder enable\n");
 	/* enable transcoder */
-	n = 0;
-	while (!((temp = INREG(transconf_reg)) & TRANS_STATE_ENABLE)) {
-	    temp |= TRANS_ENABLE;
-	    temp &= ~PIPE_BPC_MASK;
-	    temp |= pipe_bpc;
-	    OUTREG(transconf_reg, temp | TRANS_ENABLE);
-	    n++;
-	    usleep(500);
-	    if (n > 20) {
-		ErrorF("aborting transcoder %x enable\n", transconf_reg);
-		break;
-	    }
-	}
+	temp = INREG(transconf_reg);
+	temp &= ~PIPE_BPC_MASK;
+	temp |= pipe_bpc;
+	OUTREG(transconf_reg, temp | TRANS_ENABLE);
+	INREG(transconf_reg);
 
-	/* wait one idle pattern time */
-	usleep(100);
+	while ((INREG(transconf_reg) & TRANS_STATE_ENABLE) == 0)
+	    ;
 
 	ErrorF("LUT load\n");
 	i830_crtc_load_lut(crtc);
@@ -1738,14 +1757,14 @@ static void igdng_crtc_dpms(xf86CrtcPtr crtc, int mode)
     case DPMSModeOff:
 
 	ErrorF("Plane disable\n");
-	/* Disable display plane */
-	while ((temp = INREG(dspcntr_reg)) & DISPLAY_PLANE_ENABLE) {
-	    OUTREG(dspcntr_reg, temp & ~DISPLAY_PLANE_ENABLE);
-	    /* Flush the plane changes */
-	    OUTREG(dspbase_reg, INREG(dspbase_reg));
-	    INREG(dspbase_reg);
-	    usleep(10);
+	temp = INREG(dspcntr_reg);
+	if ((temp & DISPLAY_PLANE_ENABLE) != 0) {
+		OUTREG(dspcntr_reg, temp & ~DISPLAY_PLANE_ENABLE);
+		/* flush plane changes */
+		OUTREG(dspbase_reg, INREG(dspbase_reg));
+		INREG(dspbase_reg);
 	}
+
 	i830_disable_vga_plane (crtc);
 
 	ErrorF("Pipe disable\n");
@@ -1759,7 +1778,7 @@ static void igdng_crtc_dpms(xf86CrtcPtr crtc, int mode)
 	    while ((INREG(pipeconf_reg) & I965_PIPECONF_ACTIVE) != 0) {
 		n++;
 		if (n < 60) {
-		    usleep(5000);
+		    usleep(500);
 		    continue;
 		} else {
 		    ErrorF("aborting pipeconf disable early\n");
@@ -1768,26 +1787,28 @@ static void igdng_crtc_dpms(xf86CrtcPtr crtc, int mode)
 	    }
 	}
 
+	usleep(100);
+
 	ErrorF("PFIT disable\n");
-	/* Disable PF */
-	while ((temp = INREG(pf_ctl_reg)) & PF_ENABLE) {
-	    OUTREG(pf_ctl_reg, temp & ~PF_ENABLE);
-	    usleep(10);
+	temp = INREG(pf_ctl_reg);
+	if ((temp & PF_ENABLE) != 0) {
+		OUTREG(pf_ctl_reg, temp & ~PF_ENABLE);
+		INREG(pf_ctl_reg);
 	}
 	OUTREG(pf_win_size, 0);
+	INREG(pf_win_size);
 
 	ErrorF("FDI TX disable\n");
-	/* disable CPU FDI tx and PCH FDI rx */
-	while ((temp = INREG(fdi_tx_reg)) & FDI_TX_ENABLE) {
-	    OUTREG(fdi_tx_reg, temp & ~FDI_TX_ENABLE);
-	    usleep(10);
-	}
+	temp = INREG(fdi_tx_reg);
+	OUTREG(fdi_tx_reg, temp & ~FDI_TX_ENABLE);
+	INREG(fdi_tx_reg);
 
 	ErrorF("FDI RX disable\n");
-	while ((temp = INREG(fdi_rx_reg)) & FDI_RX_ENABLE) {
-	    OUTREG(fdi_rx_reg, temp & ~FDI_RX_ENABLE);
-	    usleep(10);
-	}
+	temp = INREG(fdi_rx_reg);
+	temp &= ~(0x07 << 16);
+	temp |= pipe_bpc << 11;
+	OUTREG(fdi_rx_reg, temp & ~FDI_RX_ENABLE);
+	INREG(fdi_rx_reg);
 
 	usleep(100);
 
@@ -1797,19 +1818,22 @@ static void igdng_crtc_dpms(xf86CrtcPtr crtc, int mode)
 	temp &= ~FDI_LINK_TRAIN_NONE;
 	temp |= FDI_LINK_TRAIN_PATTERN_1;
 	OUTREG(fdi_tx_reg, temp);
+	INREG(fdi_tx_reg);
 
 	ErrorF("FDI RX train 1 preload\n");
 	temp = INREG(fdi_rx_reg);
 	temp &= ~FDI_LINK_TRAIN_NONE;
 	temp |= FDI_LINK_TRAIN_PATTERN_1;
 	OUTREG(fdi_rx_reg, temp);
+	INREG(fdi_rx_reg);
 
 	usleep(100);
 
 	ErrorF("LVDS port force off\n");
 	if (i830PipeHasType(crtc, I830_OUTPUT_LVDS)) {
 	    while ((temp = INREG(PCH_LVDS)) & PORT_ENABLE) {
-		OUTREG(PCH_LVDS, temp & ~PORT_ENABLE);
+		OUTREG(PCH_LVDS, temp & ~LVDS_PORT_EN);
+		INREG(PCH_LVDS);
 		usleep(100);
 	    }
 	}
@@ -1834,32 +1858,37 @@ static void igdng_crtc_dpms(xf86CrtcPtr crtc, int mode)
 	    }
 	}
 
+	temp = INREG(transconf_reg);
+	temp &= ~PIPE_BPC_MASK;
+	temp |= pipe_bpc;
+	OUTREG(transconf_reg, temp);
+	INREG(transconf_reg);
+	usleep(100);
+
 	ErrorF("PCH DPLL disable\n");
 	/* disable PCH DPLL */
-	while ((temp = INREG(pch_dpll_reg)) & DPLL_VCO_ENABLE) {
-	    OUTREG(pch_dpll_reg, temp & ~DPLL_VCO_ENABLE);
-	    usleep(10);
-	}
+	temp = INREG(pch_dpll_reg);
+	OUTREG(pch_dpll_reg, temp & ~DPLL_VCO_ENABLE);
+	INREG(pch_dpll_reg);
 
 	ErrorF("FDI RX PLL PCD disable\n");
-	while ((temp = INREG(fdi_rx_reg)) & FDI_SEL_PCDCLK) {
-	    temp &= ~FDI_SEL_PCDCLK;
-	    OUTREG(fdi_rx_reg, temp);
-	    usleep(10);
-	}
+	temp = INREG(fdi_rx_reg);
+	temp &= ~FDI_SEL_PCDCLK;
+	OUTREG(fdi_rx_reg, temp);
+	temp = INREG(fdi_rx_reg);
 
-	ErrorF("FDI RX PLL disable\n");
-	while ((temp = INREG(fdi_rx_reg)) & FDI_RX_PLL_ENABLE) {
-	    temp &= ~FDI_RX_PLL_ENABLE;
-	    OUTREG(fdi_rx_reg, temp);
-	    usleep(10);
-	}
+	ErrorF("FDI TX PLL disable %08x\n", temp);
+	temp = INREG(fdi_tx_reg);
+	temp &= ~FDI_TX_PLL_ENABLE;
+	OUTREG(fdi_tx_reg, temp);
+	temp = INREG(fdi_tx_reg);
+	usleep(100);
 
-	ErrorF("FDI TX PLL disable\n");
-	while ((temp = INREG(fdi_tx_reg)) & FDI_RX_PLL_ENABLE) {
-	    OUTREG(fdi_tx_reg, temp & ~FDI_TX_PLL_ENABLE);
-	    usleep(10);
-	}
+	ErrorF("FDI RX PLL disable %08x\n", temp);
+	temp = INREG(fdi_tx_reg);
+	OUTREG(fdi_tx_reg, temp & ~FDI_TX_PLL_ENABLE);
+	INREG(fdi_tx_reg);
+	usleep(100);
 
 	ErrorF("DPMS off done\n");
 	/* Wait for the clocks to turn off. */
diff --git a/src/i830_lvds.c b/src/i830_lvds.c
index 34b3cbce..8f7044d9 100644
--- a/src/i830_lvds.c
+++ b/src/i830_lvds.c
@@ -510,68 +510,49 @@ i830SetLVDSPanelPower(xf86OutputPtr output, Bool on)
     struct i830_lvds_priv   *dev_priv = intel_output->dev_priv;
     ScrnInfoPtr		    scrn = output->scrn;
     intel_screen_private    *intel = intel_get_screen_private(scrn);
-    uint32_t		    pp_status, ctl_reg, status_reg;
+    uint32_t		    pp_status, ctl_reg, status_reg, lvds_reg;
 
     if (IS_IGDNG(intel)) {
 	ctl_reg = PCH_PP_CONTROL;
 	status_reg = PCH_PP_STATUS;
+	lvds_reg = PCH_LVDS;
     } else {
 	ctl_reg = PP_CONTROL;
 	status_reg = PP_STATUS;
-    }
-
-    if (IS_IGDNG(intel)) {
-	CARD32 temp;
-	if (on) {
-	    temp = INREG(PCH_LVDS);
-	    OUTREG(PCH_LVDS, temp | PORT_ENABLE);
-	    temp = INREG(PCH_LVDS);
-	} else {
-	    temp = INREG(PCH_LVDS);
-	    OUTREG(PCH_LVDS, temp & ~PORT_ENABLE);
-	    temp = INREG(PCH_LVDS);
-	}
-	usleep(100);
+	lvds_reg = LVDS;
     }
 
     if (on) {
-	/* if we're going from on->on, be aware to current level. */
-	if ((INREG(ctl_reg) & POWER_TARGET_ON) && !dev_priv->dpmsoff) 
-	    dev_priv->backlight_duty_cycle = dev_priv->get_backlight(output);
+	OUTREG(lvds_reg, INREG(lvds_reg) | LVDS_PORT_EN);
+	INREG(lvds_reg);
 
-	/*
-	 * If we're going from off->on we may need to turn on the backlight.
-	 * We should use the saved value whenever possible, but on some
-	 * machines 0 is a valid backlight value (due to an external backlight
-	 * controller for example), so on them, when turning LVDS back on,
-	 * they'll always re-maximize the brightness.
-	 */
 	if (!(INREG(ctl_reg) & POWER_TARGET_ON) &&
 	    dev_priv->backlight_duty_cycle == 0 &&
 	    intel->backlight_control_method < BCM_KERNEL)
 	    dev_priv->backlight_duty_cycle = dev_priv->backlight_max;
 
 	OUTREG(ctl_reg, INREG(ctl_reg) | POWER_TARGET_ON);
+	INREG(ctl_reg);
 	do {
 	    pp_status = INREG(status_reg);
 	} while ((pp_status & PP_ON) == 0);
 
+	/* set backlight */
 	dev_priv->set_backlight(output, dev_priv->backlight_duty_cycle);
 	dev_priv->dpmsoff = FALSE;
     } else {
-	/*
-	 * Only save the current backlight value if we're going from
-	 * on to off.
-	 */
 	if ((INREG(ctl_reg) & POWER_TARGET_ON) && !dev_priv->dpmsoff)
 	    dev_priv->backlight_duty_cycle = dev_priv->get_backlight(output);
 	dev_priv->set_backlight(output, 0);
 
 	OUTREG(ctl_reg, INREG(ctl_reg) & ~POWER_TARGET_ON);
+	INREG(ctl_reg);
 	do {
 	    pp_status = INREG(status_reg);
 	} while (pp_status & PP_ON);
-
+	
+	OUTREG(lvds_reg, INREG(lvds_reg) & ~LVDS_PORT_EN);
+	INREG(lvds_reg);
 	dev_priv->dpmsoff = TRUE;
     }
 }