On Fri, 13 Nov 2015, Bob Paauwe <bob.j.paauwe@xxxxxxxxx> wrote: > On Fri, 13 Nov 2015 19:29:41 +0200 > Mika Kuoppala <mika.kuoppala@xxxxxxxxxxxxxxx> wrote: > >> When we set and later readback a frequency value through >> sysfs interface, igt/pm_rpm assumes that we get same value back >> if it matches hw granularity. >> >> On bxt we have found out that this is not always the case. >> Currently frequency - hw ratio - frequency conversions round down, >> with few exceptions on platforms that have more specific conversions. >> On bxt the supported range can be for example from 100Mhz to 650Mhz. >> Midpoint is then calculated by test to be 375 which pm_rps uses to find a >> closest hw supported frequency. That is 366 (ratio 22), >> which it then writes back. But as the rounding down kicks in, >> driver actually sets 350 instead of 366, as 366 is 2/3 below 22 * 50/3. >> >> Fix this by rounding to closest instead of rounding down in >> freq-ratio-freq conversions. >> >> Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=92768 >> Testcase: igt/pm_rps/basic-api >> Tested-by: Bob Paauwe <bob.j.paauwe@xxxxxxxxx> >> Cc: Bob Paauwe <bob.j.paauwe@xxxxxxxxx> >> Signed-off-by: Imre Deak <imre.deak@xxxxxxxxx> >> Signed-off-by: Mika Kuoppala <mika.kuoppala@xxxxxxxxx> >> --- >> drivers/gpu/drm/i915/intel_pm.c | 8 +++++--- >> 1 file changed, 5 insertions(+), 3 deletions(-) >> >> diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c >> index 647c0ff..740623f 100644 >> --- a/drivers/gpu/drm/i915/intel_pm.c >> +++ b/drivers/gpu/drm/i915/intel_pm.c >> @@ -7139,7 +7139,8 @@ static int chv_freq_opcode(struct drm_i915_private *dev_priv, int val) >> int intel_gpu_freq(struct drm_i915_private *dev_priv, int val) >> { >> if (IS_GEN9(dev_priv->dev)) >> - return (val * GT_FREQUENCY_MULTIPLIER) / GEN9_FREQ_SCALER; >> + return DIV_ROUND_CLOSEST(val * GT_FREQUENCY_MULTIPLIER, >> + GEN9_FREQ_SCALER); >> else if (IS_CHERRYVIEW(dev_priv->dev)) >> return chv_gpu_freq(dev_priv, val); >> else if (IS_VALLEYVIEW(dev_priv->dev)) >> @@ -7151,13 +7152,14 @@ int intel_gpu_freq(struct drm_i915_private *dev_priv, int val) >> int intel_freq_opcode(struct drm_i915_private *dev_priv, int val) >> { >> if (IS_GEN9(dev_priv->dev)) >> - return (val * GEN9_FREQ_SCALER) / GT_FREQUENCY_MULTIPLIER; >> + return DIV_ROUND_CLOSEST(val * GEN9_FREQ_SCALER, >> + GT_FREQUENCY_MULTIPLIER); >> else if (IS_CHERRYVIEW(dev_priv->dev)) >> return chv_freq_opcode(dev_priv, val); >> else if (IS_VALLEYVIEW(dev_priv->dev)) >> return byt_freq_opcode(dev_priv, val); >> else >> - return val / GT_FREQUENCY_MULTIPLIER; >> + return DIV_ROUND_CLOSEST(val, GT_FREQUENCY_MULTIPLIER); >> } >> >> struct request_boost { > > Reviewed-by: Bob Paauwe <bob.j.paauwe@xxxxxxxxx> Pushed to drm-intel-fixes, thanks for the patch and review. BR, Jani. -- Jani Nikula, Intel Open Source Technology Center _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx http://lists.freedesktop.org/mailman/listinfo/intel-gfx
