Re: [PATCH 4/7] drm/i915/skl: Updated the gen6_rps_limits function

From: Damien Lespiau <damien.lespiau@intel.com>
To: akash.goel@intel.com
Cc: intel-gfx@lists.freedesktop.org
Subject: Re: [PATCH 4/7] drm/i915/skl: Updated the gen6_rps_limits function
Date: Tue, 17 Feb 2015 15:01:39 +0000	[thread overview]
Message-ID: <20150217150139.GA23520@strange.ger.corp.intel.com> (raw)
In-Reply-To: <20150217144456.GC18727@strange.ger.corp.intel.com>

On Tue, Feb 17, 2015 at 02:44:56PM +0000, Damien Lespiau wrote:
> On Fri, Feb 06, 2015 at 08:26:35PM +0530, akash.goel@intel.com wrote:
> > +	if (IS_GEN9(dev_priv->dev)) {
> > +		limits = (dev_priv->rps.max_freq_softlimit * GEN9_FREQ_SCALER) << 23;
> > +		if (val <= dev_priv->rps.min_freq_softlimit)
> > +			limits |= (dev_priv->rps.min_freq_softlimit * GEN9_FREQ_SCALER) << 14;
> 
> I believe the values here are in 16.666 Mhz, the power spec I have gives
> examples:
>   [31:23]=54d: No interrupt if already >=900MHz
>   [22:14]=18d: No interrupt if already <= 300MHz
> 
> and 54 * 16.66.. = 900.

Right, so RP_STATE_CAP is documented using 50Mhz units, so the above is
correct. How about unifying all values for SKL to the same units (always
16.66 Mhz units)? that would remove some of the confusion a bit.

-- 
Damien
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