Re: [PATCH] drm/i915/psr: Adds psrwake options for all platforms

From: Rodrigo Vivi <rodrigo.vivi@intel.com>
To: "Pandiyan, Dhinakaran" <dhinakaran.pandiyan@intel.com>
Cc: "Nikula, Jani" <jani.nikula@intel.com>,
	"intel-gfx@lists.freedesktop.org"
	<intel-gfx@lists.freedesktop.org>,
	"puthik@chromium.org" <puthik@chromium.org>
Subject: Re: [PATCH] drm/i915/psr: Adds psrwake options for all platforms
Date: Thu, 14 Jun 2018 09:48:17 -0700	[thread overview]
Message-ID: <20180614164817.GD8374@intel.com> (raw)
In-Reply-To: <1528993561.7432.57.camel@intel.com>

On Thu, Jun 14, 2018 at 09:00:15AM -0700, Pandiyan, Dhinakaran wrote:
> On Thu, 2018-06-14 at 11:59 +0530, Nagaraju, Vathsala wrote:
> > 
> > On 6/13/2018 11:10 PM, Dhinakaran Pandiyan wrote:
> > > 
> > > On Wed, 2018-06-13 at 10:32 -0700, Dhinakaran Pandiyan wrote:
> > > > 
> > > > On Wed, 2018-06-13 at 09:41 +0300, Jani Nikula wrote:
> > > > > 
> > > > > On Wed, 13 Jun 2018, "Nagaraju, Vathsala" <vathsala.nagaraju@in
> > > > > tel.
> > > > > co
> > > > > m> wrote:
> > > > > > 
> > > > > > 
> > > > > > On 6/12/2018 2:30 PM, Jani Nikula wrote:
> > > > > > > 
> > > > > > > 
> > > > > > > On Tue, 12 Jun 2018, vathsala nagaraju <vathsala.nagaraju@i
> > > > > > > ntel
> > > > > > > .c
> > > > > > > om> wrote:
> > > > > > > > 
> > > > > > > > 
> > > > > > > > From: Vathsala Nagaraju <vathsala.nagaraju@intel.com>
> > > > > > > > 
> > > > > > > > Adds new psrwake options defined in the below table.
> > > > > > > > Platform	PSR wake options vbt version
> > > > > > > > KBL/CFL/WHL	All
> > > > > > > > SKL		All PV releases (Check for 203+ might
> > > > > > > > help
> > > > > > > > but cannot be foolproof)
> > > > > > > > BXT		Uses old interpretation.
> > > > > > > > CNL/ICL+	All
> > > > > > > > GLK		All
> > > > > > > > 
> > > > > > > > For SKL, we will continue to use older interpretation for
> > > > > > > > the
> > > > > > > > above reason.
> > > > > > > > 
> > > > > > > > Cc: Jani Nikula <jani.nikula@intel.com>
> > > > > > > > Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
> > > > > > > > Cc: Puthikorn Voravootivat <puthik@chromium.org>
> > > > > > > > Cc: Dhinakaran Pandiyan <dhinakaran.pandiyan@intel.com>
> > > > > > > > 
> > > > > > > > Signed-off-by: Vathsala Nagaraju <vathsala.nagaraju@intel
> > > > > > > > .com
> > > > > > > > ---
> > > > > > > >    drivers/gpu/drm/i915/intel_bios.c | 3 ++-
> > > > > > > >    1 file changed, 2 insertions(+), 1 deletion(-)
> > > > > > > > 
> > > > > > > > diff --git a/drivers/gpu/drm/i915/intel_bios.c
> > > > > > > > b/drivers/gpu/drm/i915/intel_bios.c
> > > > > > > > index 465dff4..010ff68 100644
> > > > > > > > --- a/drivers/gpu/drm/i915/intel_bios.c
> > > > > > > > +++ b/drivers/gpu/drm/i915/intel_bios.c
> > > > > > > > @@ -710,7 +710,8 @@ static int
> > > > > > > > intel_bios_ssc_frequency(struct
> > > > > > > > drm_i915_private *dev_priv,
> > > > > > > >    	 * New psr options 0=500us, 1=100us, 2=2500us,
> > > > > > > > 3=0us
> > > > > > > >    	 * Old decimal value is wake up time in
> > > > > > > > multiples
> > > > > > > > of
> > > > > > > > 100 us.
> > > > > > > >    	 */
> > > > > > > > -	if (bdb->version >= 209 && IS_GEN9_BC(dev_priv))
> > > > > > > > {
> > > > > > > > +	if ((INTEL_GEN(dev_priv) >= 10) ||
> > > > > > > > +	    (IS_GEN9_BC(dev_priv) &&
> > > > > > > > !IS_SKYLAKE(dev_priv)))
> > > > > > > > {
> > > > > > > Please keep the version check.
> > > > > > Sure. For SKL , shall we use older interpretation for all bdb
> > > > > > version as
> > > > > > vbt team cannot confirm bdb version for SKL?
> > > > > I guess.
> > > > > 
> > > > Why not change the version check to >= 203, if that's what PV
> > > > releases
> > > > had as per your commit message? With the current code, Linux and
> > > > Windows set 500 us and 2.5 ms respectively on my laptop.
> > > Said laptop is a SKL with bdb version 205.
> > + ashutosh(VBT team)
> > Since VBT team cannot confirm version for SKL ,so skipped for
> > skylake.
> > I did a copy paste of the table provided by vbt team, will edit for
> > skylake.
> > 
> We are not going to get this right for all combinations,

:(
it seems we have to live with it

> the best we
> can do is make sure things work in most cases.

I agree.

> I prefer to err on the
> side of using the new mapping because when translated incorrectly, 3
> out of 4 values lead to >= intended training time. Given the fact that
> SKL PV releases also used the new mapping, I suggest you do this
> 
> if ((bdb->version >= 203 && IS_GEN9_BC(dev_priv)) ||
> IS_GEMINILAKE(dev_priv) ||  INTEL_GEN(dev_priv) >= 10) {

+1

> /* new mapping */
> 
> }
> 
> I don't know what the basis for the current check for version 209 is,
> other than it was the version on the KBL you tested.
> 
> -DK
> 
> 
> 
> 
> 
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