| From 883abb10f493df4a0f87562511b67ac835b41b09 Mon Sep 17 00:00:00 2001 |
| From: Chris Wilson <chris@chris-wilson.co.uk> |
| Date: Wed, 25 Sep 2013 14:24:01 -0700 |
| Subject: 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 <chris@chris-wilson.co.uk> |
| Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org> |
| Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch> |
| (cherry picked from commit 662c6ecbcdca1fe8a5402f6c83d98d242917a043) |
| Signed-off-by: Darren Hart <dvhart@linux.intel.com> |
| --- |
| drivers/gpu/drm/i915/intel_display.c | 8 +++----- |
| 1 file changed, 3 insertions(+), 5 deletions(-) |
| |
| diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c |
| index 32f8e8b81e67..2fc00349479b 100644 |
| --- a/drivers/gpu/drm/i915/intel_display.c |
| +++ b/drivers/gpu/drm/i915/intel_display.c |
| @@ -5080,7 +5080,7 @@ 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)); |
| @@ -5092,10 +5092,8 @@ 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; |
| } |
| -- |
| 1.8.5.rc3 |
| |
