From: Chris Wilson Date: Wed, 25 Sep 2013 21:24:01 +0000 (-0700) Subject: drm/i915/vlv: fix up broken precision in vlv_crtc_clock_get X-Git-Tag: v3.13-rc1~69^2~81^2~52 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=662c6ecbcdca1fe8a5402f6c83d98d242917a043;p=platform%2Fkernel%2Flinux-stable.git drm/i915/vlv: fix up broken precision in vlv_crtc_clock_get With some divider values we end up with the wrong result. So remove the intermediates (like Ville suggested in the first place) to get the right answer. Signed-off-by: Chris Wilson Signed-off-by: Jesse Barnes Signed-off-by: Daniel Vetter --- diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c index 5b52ab0..f52e6d4 100644 --- a/drivers/gpu/drm/i915/intel_display.c +++ b/drivers/gpu/drm/i915/intel_display.c @@ -5084,7 +5084,7 @@ static void vlv_crtc_clock_get(struct intel_crtc *crtc, int pipe = pipe_config->cpu_transcoder; intel_clock_t clock; u32 mdiv; - int refclk = 100000, fastclk, update_rate; + int refclk = 100000; mutex_lock(&dev_priv->dpio_lock); mdiv = vlv_dpio_read(dev_priv, pipe, DPIO_DIV(pipe)); @@ -5096,10 +5096,8 @@ static void vlv_crtc_clock_get(struct intel_crtc *crtc, clock.p1 = (mdiv >> DPIO_P1_SHIFT) & 7; clock.p2 = (mdiv >> DPIO_P2_SHIFT) & 0x1f; - update_rate = refclk / clock.n; - clock.vco = update_rate * clock.m1 * clock.m2; - fastclk = clock.vco / clock.p1 / clock.p2; - clock.dot = (2 * fastclk); + clock.vco = refclk * clock.m1 * clock.m2 / clock.n; + clock.dot = 2 * clock.vco / (clock.p1 * clock.p2); pipe_config->port_clock = clock.dot / 10; }