drm/i915: Restore the DPLL calculation logic for 9xx platform

The DPLL calculation logic for 9xx platform is changed in:
commit 652c393a3368af84359da37c45afc35a91144960
Author: Jesse Barnes <jbarnes@virtuousgeek.org>
Date:   Mon Aug 17 13:31:43 2009 -0700

    drm/i915: add dynamic clock frequency control

Maybe we will get the different M/N/P combination with that by using the
previous dpll calculation logic.

So restore the DPLL calculation logic for 9xx platform.

Signed-off-by: Zhao Yakui <yakui.zhao@intel.com>
Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Eric Anholt <eric@anholt.net>

1 files changed, 11 insertions, 10 deletions

diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index a65838ed24b9..e25601bbcb57 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -706,16 +706,17 @@ intel_find_best_PLL(const intel_limit_t *limit, struct drm_crtc *crtc,
 
         memset (best_clock, 0, sizeof (*best_clock));
 
-        for (clock.p1 = limit->p1.max; clock.p1 >= limit->p1.min; clock.p1--) {
-                for (clock.m1 = limit->m1.min; clock.m1 <= limit->m1.max;
-                     clock.m1++) {
-                        for (clock.m2 = limit->m2.min;
-                             clock.m2 <= limit->m2.max; clock.m2++) {
-                                /* m1 is always 0 in IGD */
-                                if (clock.m2 >= clock.m1 && !IS_IGD(dev))
-                                        break;
-                                for (clock.n = limit->n.min;
-                                     clock.n <= limit->n.max; clock.n++) {
+        for (clock.m1 = limit->m1.min; clock.m1 <= limit->m1.max;
+             clock.m1++) {
+                for (clock.m2 = limit->m2.min;
+                     clock.m2 <= limit->m2.max; clock.m2++) {
+                        /* m1 is always 0 in IGD */
+                        if (clock.m2 >= clock.m1 && !IS_IGD(dev))
+                                break;
+                        for (clock.n = limit->n.min;
+                             clock.n <= limit->n.max; clock.n++) {
+                                for (clock.p1 = limit->p1.min;
+                                        clock.p1 <= limit->p1.max; clock.p1++) {
                                         int this_err;
 
                                         intel_clock(dev, refclk, &clock);