[Intel-gfx] [PATCH 2/8] drm/i915: introduce intel_has_sagv()

[Jani Nikula]

On Sat, 10 Sep 2016, Ville Syrjälä <ville.syrjala at linux.intel.com> wrote:
> On Fri, Sep 09, 2016 at 07:51:15PM +0000, Zanoni, Paulo R wrote:
>> Em Sex, 2016-09-09 às 11:06 +0300, Jani Nikula escreveu:
>> > On Thu, 08 Sep 2016, Lyude Paul <cpaul at redhat.com> wrote:
>> > > 
>> > > On Thu, 2016-09-08 at 11:59 +0300, Jani Nikula wrote:
>> > > > 
>> > > > On Wed, 07 Sep 2016, Lyude <cpaul at redhat.com> wrote:
>> > > > > 
>> > > > > 
>> > > > > On Tue, 2016-09-06 at 21:52 -0300, Paulo Zanoni wrote:
>> > > > > > 
>> > > > > > +static bool
>> > > > > > +intel_has_sagv(struct drm_i915_private *dev_priv)
>> > > > > > +{
>> > > > > > +	return IS_SKYLAKE(dev_priv);
>> > > > > > +}
>> > > > > > +
>> > > > > 
>> > > > > Not sure I agree on this one. Even if a system is skylake or
>> > > > > kabylake,
>> > > > > there's a couple of very early skylake machines that don't
>> > > > > actually
>> > > > > have an SAGV on them. Hence the I915_SAGV_NOT_CONTROLLED value
>> > > > > we set
>> > > > > if we get mailbox errors.
>> > > > 
>> > > > If by "very early" you mean pre-production, we don't care.
>> 
>> Ok, so I'd like some clarification regarding this from the maintainers.
>> I always thought we didn't really care, but do this:
>> 
>> $ git grep _REVID_
>> 
>> If we don't care, why do we have this? Newer platforms also have this.
>> And many of these REVID checks are only pre-prod.
>
> For some reason no one has stepped up to remove them.

All the pre-production revid checks for each platform should be thrown
out when production hardware is readily available and in CI. We've had
this discussion before [1], but nobody has still stepped up. Perhaps
because this would involve checking and double checking what the first
shipped revision really was...

We're just hurting ourselves catering for a tiny portion of people who
still have pre-production hardware laying around. We should just warn
and taint the kernel for them.

BR,
Jani.


[1] http://mid.mail-archive.com/87inykiz6f.fsf@intel.com



-- 
Jani Nikula, Intel Open Source Technology Center