[PATCH] rework radeonfb blanking

This patch cleans up some old cruft in the manipulation of the LVDS
interface registers and fixes the blanking code to work with various DVI
flat panels.

Since this is all very sensitive stuff, I'm posting the patch here for
testing before submitting it upstream, though Andrew is welcome to put it
in -mm.

It also fix some problems with getting the right PLL setup on recent Mac
laptops, replacing the old hard coded list of values with cleaner code that
"probes" the PLL setup done by the firmware.
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

drivers/video/aty/radeon_base.c

@@ -527,8 +527,7 @@ static int __devinit radeon_probe_pll_params(struct radeonfb_info *rinfo)
         break;
 	}
 
-	OUTREG8(CLOCK_CNTL_INDEX, 1);
-	ppll_div_sel = INREG8(CLOCK_CNTL_DATA + 1) & 0x3;
+	ppll_div_sel = INREG(CLOCK_CNTL_INDEX + 1) & 0x3;
 
 	n = (INPLL(PPLL_DIV_0 + ppll_div_sel) & 0x7ff);
 	m = (INPLL(PPLL_REF_DIV) & 0x3ff);
@@ -595,53 +594,10 @@ static int __devinit radeon_probe_pll_params(struct radeonfb_info *rinfo)
  */
 static void __devinit radeon_get_pllinfo(struct radeonfb_info *rinfo)
 {
-#ifdef CONFIG_PPC_OF
-	/*
-	 * Retreive PLL infos from Open Firmware first
-	 */
-       	if (!force_measure_pll && radeon_read_xtal_OF(rinfo) == 0) {
-       		printk(KERN_INFO "radeonfb: Retreived PLL infos from Open Firmware\n");
-       		rinfo->pll.ref_div = INPLL(PPLL_REF_DIV) & 0x3ff;
-		/* FIXME: Max clock may be higher on newer chips */
-       		rinfo->pll.ppll_min = 12000;
-       		rinfo->pll.ppll_max = 35000;
-		goto found;
-	}
-#endif /* CONFIG_PPC_OF */
-
-	/*
-	 * Check out if we have an X86 which gave us some PLL informations
-	 * and if yes, retreive them
-	 */
-	if (!force_measure_pll && rinfo->bios_seg) {
-		u16 pll_info_block = BIOS_IN16(rinfo->fp_bios_start + 0x30);
-
-		rinfo->pll.sclk		= BIOS_IN16(pll_info_block + 0x08);
-		rinfo->pll.mclk		= BIOS_IN16(pll_info_block + 0x0a);
-		rinfo->pll.ref_clk	= BIOS_IN16(pll_info_block + 0x0e);
-		rinfo->pll.ref_div	= BIOS_IN16(pll_info_block + 0x10);
-		rinfo->pll.ppll_min	= BIOS_IN32(pll_info_block + 0x12);
-		rinfo->pll.ppll_max	= BIOS_IN32(pll_info_block + 0x16);
-
-		printk(KERN_INFO "radeonfb: Retreived PLL infos from BIOS\n");
-		goto found;
-	}
-
-	/*
-	 * We didn't get PLL parameters from either OF or BIOS, we try to
-	 * probe them
-	 */
-	if (radeon_probe_pll_params(rinfo) == 0) {
-		printk(KERN_INFO "radeonfb: Retreived PLL infos from registers\n");
-		/* FIXME: Max clock may be higher on newer chips */
-       		rinfo->pll.ppll_min = 12000;
-       		rinfo->pll.ppll_max = 35000;
-		goto found;
-	}
-
 	/*
-	 * Neither of the above worked, we have a few default values, though
-	 * that's mostly incomplete
+	 * In the case nothing works, these are defaults; they are mostly
+	 * incomplete, however.  It does provide ppll_max and _min values
+	 * even for most other methods, however.
 	 */
 	switch (rinfo->chipset) {
 	case PCI_DEVICE_ID_ATI_RADEON_QW:
@@ -697,6 +653,47 @@ static void __devinit radeon_get_pllinfo(struct radeonfb_info *rinfo)
 	}
 	rinfo->pll.ref_div = INPLL(PPLL_REF_DIV) & 0x3ff;
 
+
+#ifdef CONFIG_PPC_OF
+	/*
+	 * Retreive PLL infos from Open Firmware first
+	 */
+       	if (!force_measure_pll && radeon_read_xtal_OF(rinfo) == 0) {
+       		printk(KERN_INFO "radeonfb: Retreived PLL infos from Open Firmware\n");
+		goto found;
+	}
+#endif /* CONFIG_PPC_OF */
+
+	/*
+	 * Check out if we have an X86 which gave us some PLL informations
+	 * and if yes, retreive them
+	 */
+	if (!force_measure_pll && rinfo->bios_seg) {
+		u16 pll_info_block = BIOS_IN16(rinfo->fp_bios_start + 0x30);
+
+		rinfo->pll.sclk		= BIOS_IN16(pll_info_block + 0x08);
+		rinfo->pll.mclk		= BIOS_IN16(pll_info_block + 0x0a);
+		rinfo->pll.ref_clk	= BIOS_IN16(pll_info_block + 0x0e);
+		rinfo->pll.ref_div	= BIOS_IN16(pll_info_block + 0x10);
+		rinfo->pll.ppll_min	= BIOS_IN32(pll_info_block + 0x12);
+		rinfo->pll.ppll_max	= BIOS_IN32(pll_info_block + 0x16);
+
+		printk(KERN_INFO "radeonfb: Retreived PLL infos from BIOS\n");
+		goto found;
+	}
+
+	/*
+	 * We didn't get PLL parameters from either OF or BIOS, we try to
+	 * probe them
+	 */
+	if (radeon_probe_pll_params(rinfo) == 0) {
+		printk(KERN_INFO "radeonfb: Retreived PLL infos from registers\n");
+		goto found;
+	}
+
+	/*
+	 * Fall back to already-set defaults...
+	 */
        	printk(KERN_INFO "radeonfb: Used default PLL infos\n");
 
 found:
@@ -715,6 +712,7 @@ static void __devinit radeon_get_pllinfo(struct radeonfb_info *rinfo)
 	       rinfo->pll.ref_div,
 	       rinfo->pll.mclk / 100, rinfo->pll.mclk % 100,
 	       rinfo->pll.sclk / 100, rinfo->pll.sclk % 100);
+	printk("radeonfb: PLL min %d max %d\n", rinfo->pll.ppll_min, rinfo->pll.ppll_max);
 }
 
 static int radeonfb_check_var (struct fb_var_screeninfo *var, struct fb_info *info)
@@ -934,18 +932,19 @@ static int radeonfb_ioctl (struct inode *inode, struct file *file, unsigned int
 }
 
 
-static int radeon_screen_blank (struct radeonfb_info *rinfo, int blank)
+static int radeon_screen_blank (struct radeonfb_info *rinfo, int blank, int mode_switch)
 {
-        u32 val = INREG(CRTC_EXT_CNTL);
-	u32 val2 = 0;
+        u32 val;
+	u32 tmp_pix_clks;
 
-	if (rinfo->mon1_type == MT_LCD)
-		val2 = INREG(LVDS_GEN_CNTL) & ~LVDS_DISPLAY_DIS;
+	if (rinfo->lock_blank)
+		return 0;
+
+	radeon_engine_idle();
 
-        /* reset it */
+	val = INREG(CRTC_EXT_CNTL);
         val &= ~(CRTC_DISPLAY_DIS | CRTC_HSYNC_DIS |
                  CRTC_VSYNC_DIS);
-
         switch (blank) {
 	case VESA_NO_BLANKING:
 		break;
@@ -958,18 +957,68 @@ static int radeon_screen_blank (struct radeonfb_info *rinfo, int blank)
 	case VESA_POWERDOWN:
 		val |= (CRTC_DISPLAY_DIS | CRTC_VSYNC_DIS |
 			CRTC_HSYNC_DIS);
-			val2 |= (LVDS_DISPLAY_DIS);
 		break;
         }
+	OUTREG(CRTC_EXT_CNTL, val);
+
 
-	radeon_fifo_wait(1);
 	switch (rinfo->mon1_type) {
+	case MT_DFP:
+		if (mode_switch)
+			break;
+		if (blank == VESA_NO_BLANKING)
+			OUTREGP(FP_GEN_CNTL, (FP_FPON | FP_TMDS_EN),
+				~(FP_FPON | FP_TMDS_EN));
+		else
+			OUTREGP(FP_GEN_CNTL, 0, ~(FP_FPON | FP_TMDS_EN));
+		break;
 	case MT_LCD:
-			OUTREG(LVDS_GEN_CNTL, val2);
+		val = INREG(LVDS_GEN_CNTL);
+		if (blank == VESA_NO_BLANKING) {
+			u32 target_val = (val & ~LVDS_DISPLAY_DIS) | LVDS_BLON | LVDS_ON
+				| LVDS_ON | (rinfo->init_state.lvds_gen_cntl & LVDS_DIGON);
+			if ((val ^ target_val) == LVDS_DISPLAY_DIS)
+				OUTREG(LVDS_GEN_CNTL, target_val);
+			else if ((val ^ target_val) != 0) {
+				del_timer_sync(&rinfo->lvds_timer);
+				OUTREG(LVDS_GEN_CNTL, target_val & ~LVDS_ON);
+				rinfo->init_state.lvds_gen_cntl &= ~LVDS_STATE_MASK;
+				rinfo->init_state.lvds_gen_cntl |= target_val & LVDS_STATE_MASK;
+				if (mode_switch) {
+					msleep(rinfo->panel_info.pwr_delay);
+					OUTREG(LVDS_GEN_CNTL, target_val);
+				}
+				else {
+					rinfo->pending_lvds_gen_cntl = target_val;
+					mod_timer(&rinfo->lvds_timer,
+						  jiffies + MS_TO_HZ(rinfo->panel_info.pwr_delay));
+				}
+			}
+		} else {
+			val |= LVDS_DISPLAY_DIS;
+			OUTREG(LVDS_GEN_CNTL, val);
+
+			/* We don't do a full switch-off on a simple mode switch */
+			if (mode_switch)
+				break;
+
+			/* Asic bug, when turning off LVDS_ON, we have to make sure
+			 * RADEON_PIXCLK_LVDS_ALWAYS_ON bit is off
+			 */
+			tmp_pix_clks = INPLL(PIXCLKS_CNTL);
+			if (rinfo->is_mobility || rinfo->is_IGP)
+				OUTPLLP(PIXCLKS_CNTL, 0, ~PIXCLK_LVDS_ALWAYS_ONb);
+			val &= ~(LVDS_BLON | LVDS_ON);
+			OUTREG(LVDS_GEN_CNTL, val);
+			rinfo->init_state.lvds_gen_cntl &= ~LVDS_STATE_MASK;
+			rinfo->init_state.lvds_gen_cntl |= val & LVDS_STATE_MASK;
+			if (rinfo->is_mobility || rinfo->is_IGP)
+				OUTPLL(PIXCLKS_CNTL, tmp_pix_clks);
+		}
 		break;
 	case MT_CRT:
+		// todo: powerdown DAC
 	default:
-		        OUTREG(CRTC_EXT_CNTL, val);
 		break;
 	}
 
@@ -983,17 +1032,7 @@ int radeonfb_blank (int blank, struct fb_info *info)
 	if (rinfo->asleep)
 		return 0;
 		
-#ifdef CONFIG_PMAC_BACKLIGHT
-	if (rinfo->mon1_type == MT_LCD && _machine == _MACH_Pmac && blank)
-		set_backlight_enable(0);
-#endif
-                        
-	radeon_screen_blank(rinfo, blank);
-
-#ifdef CONFIG_PMAC_BACKLIGHT
-	if (rinfo->mon1_type == MT_LCD && _machine == _MACH_Pmac && !blank)
-		set_backlight_enable(1);
-#endif
+	radeon_screen_blank(rinfo, blank, 0);
 
 	return 0;
 }
@@ -1225,7 +1264,8 @@ static void radeon_write_mode (struct radeonfb_info *rinfo,
 
 	del_timer_sync(&rinfo->lvds_timer);
 
-	radeon_screen_blank(rinfo, VESA_POWERDOWN);
+	radeon_screen_blank(rinfo, VESA_POWERDOWN, 1);
+	msleep(100);
 
 	radeon_fifo_wait(31);
 	for (i=0; i<10; i++)
@@ -1265,35 +1305,9 @@ static void radeon_write_mode (struct radeonfb_info *rinfo,
 		OUTREG(FP_GEN_CNTL, mode->fp_gen_cntl);
 		OUTREG(TMDS_CRC, mode->tmds_crc);
 		OUTREG(TMDS_TRANSMITTER_CNTL, mode->tmds_transmitter_cntl);
-
-		if (primary_mon == MT_LCD) {
-			unsigned int tmp = INREG(LVDS_GEN_CNTL);
-
-			/* HACK: The backlight control code may have modified init_state.lvds_gen_cntl,
-			 * so we update ourselves
-			 */
-			mode->lvds_gen_cntl &= ~LVDS_STATE_MASK;
-			mode->lvds_gen_cntl |= (rinfo->init_state.lvds_gen_cntl & LVDS_STATE_MASK);
-
-			if ((tmp & (LVDS_ON | LVDS_BLON)) ==
-			    (mode->lvds_gen_cntl & (LVDS_ON | LVDS_BLON))) {
-				OUTREG(LVDS_GEN_CNTL, mode->lvds_gen_cntl);
-			} else {
-				rinfo->pending_pixclks_cntl = INPLL(PIXCLKS_CNTL);
-				if (rinfo->is_mobility || rinfo->is_IGP)
-					OUTPLLP(PIXCLKS_CNTL, 0, ~PIXCLK_LVDS_ALWAYS_ONb);
-				if (!(tmp & (LVDS_ON | LVDS_BLON)))
-					OUTREG(LVDS_GEN_CNTL, mode->lvds_gen_cntl | LVDS_BLON);
-				rinfo->pending_lvds_gen_cntl = mode->lvds_gen_cntl;
-				mod_timer(&rinfo->lvds_timer,
-					  jiffies + MS_TO_HZ(rinfo->panel_info.pwr_delay));
-			}
 	}
-	}
-
-	RTRACE("lvds_gen_cntl: %08x\n", INREG(LVDS_GEN_CNTL));
 
-	radeon_screen_blank(rinfo, VESA_NO_BLANKING);
+	radeon_screen_blank(rinfo, VESA_NO_BLANKING, 1);
 
 	radeon_fifo_wait(2);
 	OUTPLL(VCLK_ECP_CNTL, mode->vclk_ecp_cntl);
@@ -1329,7 +1343,7 @@ static void radeon_calc_pll_regs(struct radeonfb_info *rinfo, struct radeon_regs
 	 * not sure which model starts having FP2_GEN_CNTL, I assume anything more
 	 * recent than an r(v)100...
 	 */
-#if 0
+#if 1
 	/* XXX I had reports of flicker happening with the cinema display
 	 * on TMDS1 that seem to be fixed if I also forbit odd dividers in
 	 * this case. This could just be a bandwidth calculation issue, I
@@ -1379,6 +1393,8 @@ static void radeon_calc_pll_regs(struct radeonfb_info *rinfo, struct radeon_regs
 		freq = rinfo->pll.ppll_max;
 	if (freq*12 < rinfo->pll.ppll_min)
 		freq = rinfo->pll.ppll_min / 12;
+	RTRACE("freq = %lu, PLL min = %u, PLL max = %u\n",
+	       freq, rinfo->pll.ppll_min, rinfo->pll.ppll_max);
 
 	for (post_div = &post_divs[0]; post_div->divider; ++post_div) {
 		pll_output_freq = post_div->divider * freq;
@@ -1392,6 +1408,16 @@ static void radeon_calc_pll_regs(struct radeonfb_info *rinfo, struct radeon_regs
 			break;
 	}
 
+	/* If we fall through the bottom, try the "default value"
+	   given by the terminal post_div->bitvalue */
+	if ( !post_div->divider ) {
+		post_div = &post_divs[post_div->bitvalue];
+		pll_output_freq = post_div->divider * freq;
+	}
+	RTRACE("ref_div = %d, ref_clk = %d, output_freq = %d\n",
+	       rinfo->pll.ref_div, rinfo->pll.ref_clk,
+	       pll_output_freq);
+
 	fb_div = round_div(rinfo->pll.ref_div*pll_output_freq,
 				  rinfo->pll.ref_clk);
 	regs->ppll_ref_div = rinfo->pll.ref_div;
@@ -1780,8 +1806,7 @@ static int backlight_conv_m7[] = {
 static int radeon_set_backlight_enable(int on, int level, void *data)
 {
 	struct radeonfb_info *rinfo = (struct radeonfb_info *)data;
-	unsigned int lvds_gen_cntl = INREG(LVDS_GEN_CNTL);
-	unsigned long tmpPixclksCntl = INPLL(PIXCLKS_CNTL);
+	u32 lvds_gen_cntl, tmpPixclksCntl;
 	int* conv_table;
 
 	if (rinfo->mon1_type != MT_LCD)
@@ -1803,42 +1828,47 @@ static int radeon_set_backlight_enable(int on, int level, void *data)
 		conv_table = backlight_conv_m6;
 
 	del_timer_sync(&rinfo->lvds_timer);
+	radeon_engine_idle();
 
-	lvds_gen_cntl |= (LVDS_BL_MOD_EN | LVDS_BLON);
-	radeon_fifo_wait(3);
+	lvds_gen_cntl = INREG(LVDS_GEN_CNTL);
 	if (on && (level > BACKLIGHT_OFF)) {
-		lvds_gen_cntl |= LVDS_DIGON;
-		if (!(lvds_gen_cntl & LVDS_ON)) {
-			lvds_gen_cntl &= ~LVDS_BLON;
-			OUTREG(LVDS_GEN_CNTL, lvds_gen_cntl);
-			(void)INREG(LVDS_GEN_CNTL);
-			mdelay(rinfo->panel_info.pwr_delay);/* OUCH !!! FIXME */
-			lvds_gen_cntl |= LVDS_BLON;
+		lvds_gen_cntl &= ~LVDS_DISPLAY_DIS;
+		if (!(lvds_gen_cntl & LVDS_BLON) || !(lvds_gen_cntl & LVDS_ON)) {
+			lvds_gen_cntl |= LVDS_BLON /* | LVDS_EN | LVDS_DIGON */;
 			OUTREG(LVDS_GEN_CNTL, lvds_gen_cntl);
-		}
 			lvds_gen_cntl &= ~LVDS_BL_MOD_LEVEL_MASK;
 			lvds_gen_cntl |= (conv_table[level] <<
 					  LVDS_BL_MOD_LEVEL_SHIFT);
-		lvds_gen_cntl |= (LVDS_ON | LVDS_EN);
-		lvds_gen_cntl &= ~LVDS_DISPLAY_DIS;
+			lvds_gen_cntl |= LVDS_ON;
+			rinfo->pending_lvds_gen_cntl = lvds_gen_cntl;
+			mod_timer(&rinfo->lvds_timer,
+				  jiffies + MS_TO_HZ(rinfo->panel_info.pwr_delay));
+		} else {
+			lvds_gen_cntl &= ~LVDS_BL_MOD_LEVEL_MASK;
+			lvds_gen_cntl |= (conv_table[level] <<
+					  LVDS_BL_MOD_LEVEL_SHIFT);
+			OUTREG(LVDS_GEN_CNTL, lvds_gen_cntl);
+		}
+		rinfo->init_state.lvds_gen_cntl &= ~LVDS_STATE_MASK;
+		rinfo->init_state.lvds_gen_cntl |= rinfo->pending_lvds_gen_cntl
+			& LVDS_STATE_MASK;
 	} else {
 		/* Asic bug, when turning off LVDS_ON, we have to make sure
 		   RADEON_PIXCLK_LVDS_ALWAYS_ON bit is off
 		*/
+		tmpPixclksCntl = INPLL(PIXCLKS_CNTL);
 		if (rinfo->is_mobility || rinfo->is_IGP)
 			OUTPLLP(PIXCLKS_CNTL, 0, ~PIXCLK_LVDS_ALWAYS_ONb);
 		lvds_gen_cntl &= ~LVDS_BL_MOD_LEVEL_MASK;
 		lvds_gen_cntl |= (conv_table[0] <<
 				  LVDS_BL_MOD_LEVEL_SHIFT);
-		lvds_gen_cntl |= LVDS_DISPLAY_DIS | LVDS_BLON;
+		lvds_gen_cntl |= LVDS_DISPLAY_DIS;
 		OUTREG(LVDS_GEN_CNTL, lvds_gen_cntl);
-		mdelay(rinfo->panel_info.pwr_delay);/* OUCH !!! FIXME */
-		lvds_gen_cntl &= ~(LVDS_ON | LVDS_EN | LVDS_BLON | LVDS_DIGON);
-	}
-
+		lvds_gen_cntl &= ~(LVDS_ON | LVDS_BLON /* | LVDS_EN | LVDS_DIGON */);
 		OUTREG(LVDS_GEN_CNTL, lvds_gen_cntl);
 		if (rinfo->is_mobility || rinfo->is_IGP)
 			OUTPLL(PIXCLKS_CNTL, tmpPixclksCntl);
+	}
 	rinfo->init_state.lvds_gen_cntl &= ~LVDS_STATE_MASK;
 	rinfo->init_state.lvds_gen_cntl |= (lvds_gen_cntl & LVDS_STATE_MASK);
 

drivers/video/aty/radeon_monitor.c

@@ -633,43 +633,25 @@ void __devinit radeon_probe_screens(struct radeonfb_info *rinfo,
  */
 static void radeon_fixup_panel_info(struct radeonfb_info *rinfo)
 {
+ #ifdef CONFIG_PPC_OF
 	/*
-	 * A few iBook laptop panels seem to need a fixed PLL setting
-	 *
-	 * We should probably do this differently based on the panel
-	 * type/model or eventually some other device-tree informations,
-	 * but these tweaks below work enough for now. --BenH
+	 * LCD Flat panels should use fixed dividers, we enfore that on
+	 * PowerMac only for now...
 	 */
-#ifdef CONFIG_PPC_OF
-	/* iBook2's */
-	if (machine_is_compatible("PowerBook4,3")) {
-		rinfo->panel_info.ref_divider = rinfo->pll.ref_div;
-		rinfo->panel_info.post_divider = 0x6;
-		rinfo->panel_info.fbk_divider = 0xad;
-		rinfo->panel_info.use_bios_dividers = 1;
-	}
-	/* Aluminium PowerBook 15" */
-	if (machine_is_compatible("PowerBook5,4")) {
-		rinfo->panel_info.ref_divider = rinfo->pll.ref_div;
-		rinfo->panel_info.post_divider = 0x2;
-		rinfo->panel_info.fbk_divider = 0x8e;
-		rinfo->panel_info.use_bios_dividers = 1;
-	}
-	/* Aluminium PowerBook 17" */
-	if (machine_is_compatible("PowerBook5,3") ||
-	    machine_is_compatible("PowerBook5,5")) {
-		rinfo->panel_info.ref_divider = rinfo->pll.ref_div;
-		rinfo->panel_info.post_divider = 0x4;
-		rinfo->panel_info.fbk_divider = 0x80;
-		rinfo->panel_info.use_bios_dividers = 1;
-	}
-	/* iBook G4 */
-        if (machine_is_compatible("PowerBook6,3") ||
-            machine_is_compatible("PowerBook6,5")) {
+	if (!rinfo->panel_info.use_bios_dividers && rinfo->mon1_type == MT_LCD
+	    && rinfo->is_mobility) {
+		int ppll_div_sel = INREG8(CLOCK_CNTL_INDEX + 1) & 0x3;
+		u32 ppll_divn = INPLL(PPLL_DIV_0 + ppll_div_sel);
 		rinfo->panel_info.ref_divider = rinfo->pll.ref_div;
-		rinfo->panel_info.post_divider = 0x6;
-		rinfo->panel_info.fbk_divider = 0xad;
+		rinfo->panel_info.fbk_divider = ppll_divn & 0x7ff;
+		rinfo->panel_info.post_divider = (ppll_divn >> 16) & 0x7;
 		rinfo->panel_info.use_bios_dividers = 1;
+
+		printk(KERN_DEBUG "radeonfb: Using Firmware dividers 0x%08x "
+		       "from PPLL %d\n",
+		       rinfo->panel_info.fbk_divider |
+		       (rinfo->panel_info.post_divider << 16),
+		       ppll_div_sel);
 	}
 #endif /* CONFIG_PPC_OF */
 }

drivers/video/aty/radeon_pm.c

@@ -465,7 +465,9 @@ static void radeon_pm_setup_for_suspend(struct radeonfb_info *rinfo)
 						
  	OUTPLL( pllPIXCLKS_CNTL, pixclks_cntl);
 
-
+	/* Switch off LVDS interface */
+	OUTREG(LVDS_GEN_CNTL, INREG(LVDS_GEN_CNTL) &
+	       ~(LVDS_BLON | LVDS_EN | LVDS_ON | LVDS_DIGON));
 
 	/* Enable System power management */
 	pll_pwrmgt_cntl = INPLL( pllPLL_PWRMGT_CNTL);

include/video/radeon.h

@@ -619,8 +619,7 @@
 #define LVDS_BLON				   (1 << 19)
 #define LVDS_SEL_CRTC2				   (1 << 23)
 #define LVDS_STATE_MASK	\
-	(LVDS_ON | LVDS_DISPLAY_DIS | LVDS_BL_MOD_LEVEL_MASK | \
-	 LVDS_EN | LVDS_DIGON | LVDS_BLON)
+	(LVDS_ON | LVDS_DISPLAY_DIS | LVDS_BL_MOD_LEVEL_MASK | LVDS_BLON)
 
 /* LVDS_PLL_CNTL bit constatns */
 #define HSYNC_DELAY_SHIFT			   0x1c