[PATCH] drm/i915: Use graphics ver, rel info for media on old platforms

[Sripada, Radhakrishna]

Hi Jani,

> -----Original Message-----
> From: Jani Nikula <jani.nikula at linux.intel.com>
> Sent: Tuesday, October 11, 2022 12:28 AM
> To: Sripada, Radhakrishna <radhakrishna.sripada at intel.com>; intel-
> gfx at lists.freedesktop.org
> Cc: dri-devel at lists.freedesktop.org; Sripada, Radhakrishna
> <radhakrishna.sripada at intel.com>; De Marchi, Lucas
> <lucas.demarchi at intel.com>; Roper, Matthew D
> <matthew.d.roper at intel.com>
> Subject: Re: [PATCH] drm/i915: Use graphics ver, rel info for media on old
> platforms
> 
> On Mon, 10 Oct 2022, Radhakrishna Sripada <radhakrishna.sripada at intel.com>
> wrote:
> > Platforms prior to MTL do not have a separate media and graphics version.
> > On platforms where GMD id is not supported, reuse the graphics ip version,
> > release info for media.
> >
> > The rest of the IP graphics, display versions would be copied during driver
> > creation.
> >
> > While at it warn if GMD is not used for platforms greater than gen12.
> >
> > Fixes: c2c7075225ef ("drm/i915: Read graphics/media/display arch version
> from hw")
> > Cc: Jani Nikula <jani.nikula at linux.intel.com>
> > Cc: Lucas De Marchi <lucas.demarchi at intel.com>
> > Cc: Matt Roper <matthew.d.roper at intel.com>
> > Signed-off-by: Radhakrishna Sripada <radhakrishna.sripada at intel.com>
> > ---
> >  drivers/gpu/drm/i915/intel_device_info.c | 12 +++++++++++-
> >  1 file changed, 11 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/gpu/drm/i915/intel_device_info.c
> b/drivers/gpu/drm/i915/intel_device_info.c
> > index 090097bb3c0a..ba178b61bceb 100644
> > --- a/drivers/gpu/drm/i915/intel_device_info.c
> > +++ b/drivers/gpu/drm/i915/intel_device_info.c
> > @@ -329,8 +329,18 @@ static void intel_ipver_early_init(struct
> drm_i915_private *i915)
> >  {
> >  	struct intel_runtime_info *runtime = RUNTIME_INFO(i915);
> >
> > -	if (!HAS_GMD_ID(i915))
> > +	if (!HAS_GMD_ID(i915)) {
> > +		drm_WARN_ON(&i915->drm, RUNTIME_INFO(i915)-
> >graphics.ip.ver > 12);
> > +		/*
> > +		 * On older platforms, graphics and media share the same ip
> > +		 * version and release.
> > +		 */
> > +		RUNTIME_INFO(i915)->media.ip.ver =
> > +			RUNTIME_INFO(i915)->graphics.ip.ver;
> > +		RUNTIME_INFO(i915)->media.ip.rel =
> > +			RUNTIME_INFO(i915)->graphics.ip.rel;
> 
> You could assign the whole struct ip_version (*) at once, or is there a
> reason you're intentionally not assigning step?
Step info would anyways be determined later in the function intel_step_init.
We already have macros in place to handle common gt and media steps there.

Do you suggest we memcpy(&RUNTIME_INFO(i915)->media.ip, &RUNTIME_INFO->graphics.ip, sizeof(struct ip_version)) here?

> 
> BR,
> Jani.
> 
> (*) Why does that name not have intel_ prefix?
Good question. Since introduced in " a5b7ef27da60 drm/i915: Add struct to hold IP version"
we have been using as is. The author might have felt that the structure is not big enough/used in as many places
to have an intel_ prefix. Do you see a symbol collision here that we need to add intel_ prefix? If so should we do it
in a separate patch?

Thanks,
Radhakrishna(RK) Sripada
> 
> >  		return;
> > +	}
> >
> >  	ip_ver_read(i915, i915_mmio_reg_offset(GMD_ID_GRAPHICS),
> >  		    &runtime->graphics.ip);
> 
> --
> Jani Nikula, Intel Open Source Graphics Center