From 07ab118b393410c65146f44c17b0ae5373eb972e Mon Sep 17 00:00:00 2001 From: =?UTF-8?q?Ville=20Syrj=C3=A4l=C3=A4?= Date: Tue, 5 Nov 2013 22:42:28 +0200 Subject: drm/i915: Improve vlv_gpu_freq() and vlv_freq_opcode() MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit We're currently miscalculating the VLV graphics clock a little bit. This is caused by rounding the step to integer MHz, which does not match reality. Change the formula to match the GUnit HAS to give more accurate answers. Signed-off-by: Ville Syrjälä Reviewed-by: Jesse Barnes Signed-off-by: Daniel Vetter --- drivers/gpu/drm/i915/intel_pm.c | 35 ++++++++++++----------------------- 1 file changed, 12 insertions(+), 23 deletions(-) diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c index a5778e59cc1..865035beccc 100644 --- a/drivers/gpu/drm/i915/intel_pm.c +++ b/drivers/gpu/drm/i915/intel_pm.c @@ -5947,57 +5947,46 @@ int sandybridge_pcode_write(struct drm_i915_private *dev_priv, u8 mbox, u32 val) int vlv_gpu_freq(int ddr_freq, int val) { - int mult, base; + int div; + /* 4 x czclk */ switch (ddr_freq) { case 800: - mult = 20; - base = 120; + div = 10; break; case 1066: - mult = 22; - base = 133; + div = 12; break; case 1333: - mult = 21; - base = 125; + div = 16; break; default: return -1; } - return ((val - 0xbd) * mult) + base; + return DIV_ROUND_CLOSEST(ddr_freq * (val + 6 - 0xbd), 4 * div); } int vlv_freq_opcode(int ddr_freq, int val) { - int mult, base; + int mul; + /* 4 x czclk */ switch (ddr_freq) { case 800: - mult = 20; - base = 120; + mul = 10; break; case 1066: - mult = 22; - base = 133; + mul = 12; break; case 1333: - mult = 21; - base = 125; + mul = 16; break; default: return -1; } - val /= mult; - val -= base / mult; - val += 0xbd; - - if (val > 0xea) - val = 0xea; - - return val; + return DIV_ROUND_CLOSEST(4 * mul * val, ddr_freq) + 0xbd - 6; } void intel_pm_init(struct drm_device *dev) -- cgit v1.2.3