drm/radeon/kms: display watermark fixes

- rs780/880 were using the wrong bandwidth functions
- convert r1xx-r4xx to use the same pm sclk/mclk structs as
r5xx+
- move bandwidth setup to a common function

Signed-off-by: Alex Deucher <alexdeucher@gmail.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
diff --git a/drivers/gpu/drm/radeon/r100.c b/drivers/gpu/drm/radeon/r100.c
index 9d634c8..e35cf19 100644
--- a/drivers/gpu/drm/radeon/r100.c
+++ b/drivers/gpu/drm/radeon/r100.c
@@ -2025,6 +2025,7 @@
 	radeon_vram_location(rdev, &rdev->mc, base);
 	if (!(rdev->flags & RADEON_IS_AGP))
 		radeon_gtt_location(rdev, &rdev->mc);
+	radeon_update_bandwidth_info(rdev);
 }
 
 
@@ -2416,11 +2417,8 @@
 	/*
 	 * determine is there is enough bw for current mode
 	 */
-	mclk_ff.full = rfixed_const(rdev->clock.default_mclk);
-	temp_ff.full = rfixed_const(100);
-	mclk_ff.full = rfixed_div(mclk_ff, temp_ff);
-	sclk_ff.full = rfixed_const(rdev->clock.default_sclk);
-	sclk_ff.full = rfixed_div(sclk_ff, temp_ff);
+	sclk_ff = rdev->pm.sclk;
+	mclk_ff = rdev->pm.mclk;
 
 	temp = (rdev->mc.vram_width / 8) * (rdev->mc.vram_is_ddr ? 2 : 1);
 	temp_ff.full = rfixed_const(temp);