drm/i915: Adjust DisplayPort clocks to use 96MHz reference
For some reason, the DP clocks were based off a 100MHz reference instead of
the standard 96MHz reference. This caused some DP monitors to fail to lock
to the signal.
Signed-off-by: Keith Packard <keithp@keithp.com>
Signed-off-by: Eric Anholt <eric@anholt.net>
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index 59de495..508838e 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -816,24 +816,21 @@
{
intel_clock_t clock;
if (target < 200000) {
- clock.dot = 161670;
- clock.p = 20;
clock.p1 = 2;
clock.p2 = 10;
- clock.n = 0x01;
- clock.m = 97;
- clock.m1 = 0x10;
- clock.m2 = 0x05;
+ clock.n = 2;
+ clock.m1 = 23;
+ clock.m2 = 8;
} else {
- clock.dot = 270000;
- clock.p = 10;
clock.p1 = 1;
clock.p2 = 10;
- clock.n = 0x02;
- clock.m = 108;
- clock.m1 = 0x12;
- clock.m2 = 0x06;
+ clock.n = 1;
+ clock.m1 = 14;
+ clock.m2 = 2;
}
+ clock.m = 5 * (clock.m1 + 2) + (clock.m2 + 2);
+ clock.p = (clock.p1 * clock.p2);
+ clock.dot = 96000 * clock.m / (clock.n + 2) / clock.p;
memcpy(best_clock, &clock, sizeof(intel_clock_t));
return true;
}