drm/radeon/kms: remove new pll algo

The recent changes to the old algo (prefer high post div)
coupled with the range and precision limitations of using
fixed point with the new algo make the new algo less
useful.  So drop the new algo.  This should work as well
or better than the old new/old combinations and simplifies
the code a lot.

Fixes:
https://bugs.freedesktop.org/show_bug.cgi?id=30218
among others.

Signed-off-by: Alex Deucher <alexdeucher@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
diff --git a/drivers/gpu/drm/radeon/atombios_crtc.c b/drivers/gpu/drm/radeon/atombios_crtc.c
index ca04a1b..89600e3 100644
--- a/drivers/gpu/drm/radeon/atombios_crtc.c
+++ b/drivers/gpu/drm/radeon/atombios_crtc.c
@@ -482,19 +482,6 @@
 	/* reset the pll flags */
 	pll->flags = 0;
 
-	/* select the PLL algo */
-	if (ASIC_IS_AVIVO(rdev)) {
-		if (radeon_new_pll == 0)
-			pll->algo = PLL_ALGO_LEGACY;
-		else
-			pll->algo = PLL_ALGO_NEW;
-	} else {
-		if (radeon_new_pll == 1)
-			pll->algo = PLL_ALGO_NEW;
-		else
-			pll->algo = PLL_ALGO_LEGACY;
-	}
-
 	if (ASIC_IS_AVIVO(rdev)) {
 		if ((rdev->family == CHIP_RS600) ||
 		    (rdev->family == CHIP_RS690) ||
@@ -523,25 +510,8 @@
 				/* DVO wants 2x pixel clock if the DVO chip is in 12 bit mode */
 				if (radeon_encoder->encoder_id == ENCODER_OBJECT_ID_INTERNAL_KLDSCP_DVO1)
 					adjusted_clock = mode->clock * 2;
-				if (radeon_encoder->active_device & (ATOM_DEVICE_TV_SUPPORT)) {
-					pll->algo = PLL_ALGO_LEGACY;
+				if (radeon_encoder->active_device & (ATOM_DEVICE_TV_SUPPORT))
 					pll->flags |= RADEON_PLL_PREFER_CLOSEST_LOWER;
-				}
-				/* There is some evidence (often anecdotal) that RV515/RV620 LVDS
-				 * (on some boards at least) prefers the legacy algo.  I'm not
-				 * sure whether this should handled generically or on a
-				 * case-by-case quirk basis.  Both algos should work fine in the
-				 * majority of cases.
-				 */
-				if ((radeon_encoder->active_device & (ATOM_DEVICE_LCD_SUPPORT)) &&
-				    ((rdev->family == CHIP_RV515) ||
-				     (rdev->family == CHIP_RV620))) {
-					/* allow the user to overrride just in case */
-					if (radeon_new_pll == 1)
-						pll->algo = PLL_ALGO_NEW;
-					else
-						pll->algo = PLL_ALGO_LEGACY;
-				}
 			} else {
 				if (encoder->encoder_type != DRM_MODE_ENCODER_DAC)
 					pll->flags |= RADEON_PLL_NO_ODD_POST_DIV;