drm/radeon/kms: more r4xx lvds fixes

Grab pll ref div from regs at driver init.  r4xx seems very
picky about the dividers for the pll driving lvds.
Signed-off-by: Alex Deucher <alexdeucher@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

drivers/gpu/drm/radeon/atombios_crtc.c

@@ -457,9 +457,8 @@ void atombios_crtc_set_pll(struct drm_crtc *crtc, struct drm_display_mode *mode)
 				if (encoder->encoder_type !=
 				    DRM_MODE_ENCODER_DAC)
 					pll_flags |= RADEON_PLL_NO_ODD_POST_DIV;
-				if (!ASIC_IS_AVIVO(rdev)
-				    && (encoder->encoder_type ==
-					DRM_MODE_ENCODER_LVDS))
+				if (encoder->encoder_type ==
+					DRM_MODE_ENCODER_LVDS)
 					pll_flags |= RADEON_PLL_USE_REF_DIV;
 			}
 			radeon_encoder = to_radeon_encoder(encoder);

drivers/gpu/drm/radeon/radeon_clocks.c

@@ -106,8 +106,19 @@ void radeon_get_clock_info(struct drm_device *dev)
 		ret = radeon_combios_get_clock_info(dev);
 
 	if (ret) {
-		if (p1pll->reference_div < 2)
-			p1pll->reference_div = 12;
+		if (p1pll->reference_div < 2) {
+			if (!ASIC_IS_AVIVO(rdev)) {
+				u32 tmp = RREG32_PLL(RADEON_PPLL_REF_DIV);
+				if (ASIC_IS_R300(rdev))
+					p1pll->reference_div =
+						(tmp & R300_PPLL_REF_DIV_ACC_MASK) >> R300_PPLL_REF_DIV_ACC_SHIFT;
+				else
+					p1pll->reference_div = tmp & RADEON_PPLL_REF_DIV_MASK;
+				if (p1pll->reference_div < 2)
+					p1pll->reference_div = 12;
+			} else
+				p1pll->reference_div = 12;
+		}
 		if (p2pll->reference_div < 2)
 			p2pll->reference_div = 12;
 		if (rdev->family < CHIP_RS600) {

drivers/gpu/drm/radeon/radeon_legacy_crtc.c

@@ -819,8 +819,8 @@ static void radeon_set_pll(struct drm_crtc *crtc, struct drm_display_mode *mode)
 							use_bios_divs = true;
 						}
 					}
-					pll_flags |= RADEON_PLL_USE_REF_DIV;
 				}
+				pll_flags |= RADEON_PLL_USE_REF_DIV;
 			}
 		}
 	}