Re: [PATCH] drm/i915: Export total subslice and EU counts

["Zhigang Gong" <zhigang.gong@linux.intel.com>]

> -----Original Message-----
> From: Beignet [mailto:beignet-bounces@lists.freedesktop.org] On Behalf Of
> Jeff McGee
> Sent: Saturday, March 7, 2015 2:44 AM
> To: Zhigang Gong
> Cc: daniel@ffwll.ch; intel-gfx@lists.freedesktop.org;
> beignet@lists.freedesktop.org; dri-devel@lists.freedesktop.org
> Subject: Re: [Beignet] [PATCH] drm/i915: Export total subslice and EU counts
> 
> On Thu, Mar 05, 2015 at 12:35:55PM +0800, Zhigang Gong wrote:
> > There is one minor conflict when apply the KMD patch to latest
> > drm-intel-nightly branch. It should be easy to fix.
> >
> > Another issue is that IMO, we should bump libdrm's version number when
> > increase these new APIs. Then in Beignet, we can check the libdrm
> > version at build time and determine whether we will use these new
> > interfaces. Thus, we can avoid breaking beignet on those systems which
> > have previous libdrm/kernel installed.
> >
> Right. I can append a libdrm patch to bump the version. And then I suppose I
> will follow the process to make a new release. Not sure right now how that
> works. First time going through it.
> 
> Also, how should we test for the libdrm version and conditionally use the API?
We can check the libdrm version at configuration time and define a macro to
indicate whether we can use these new APIs in beignet.
> Is there a previous example of this in Beignet that I could follow?
Yes, one example is userptr. You can check the usage of DRM_INTEL_USERPTR and HAS_USERPTR
In beignet.

Thanks,
Zhigang Gong.

> 
> Jeff
> 
> > The other parts of the whole patchset, including patches for
> > KMD/libdrm/Intel gpu tools and Beignet, all look good to me.
> >
> > And I just tested it on BDW and SKL platforms, it works fine.
> >
> > Thanks,
> > Zhigang Gong.
> >
> > On Mon, Mar 02, 2015 at 03:37:32PM -0800, jeff.mcgee@intel.com wrote:
> > > From: Jeff McGee <jeff.mcgee@intel.com>
> > >
> > > Setup new I915_GETPARAM ioctl entries for subslice total and EU
> > > total. Userspace drivers need these values when constructing GPGPU
> > > commands. This kernel query method is intended to replace the PCI
> > > ID-based tables that userspace drivers currently maintain.
> > > The kernel driver can employ fuse register reads as needed to ensure
> > > the most accurate determination of GT config attributes.
> > > This first became important with Cherryview in which the config
> > > could differ between devices with the same PCI ID.
> > >
> > > The kernel detection of these values is device-specific and not
> > > included in this patch. Because zero is not a valid value for any of
> > > these parameters, a value of zero is interpreted as unknown for the
> > > device. Userspace drivers should continue to maintain ID-based
> > > tables for older devices not supported by the new query method.
> > >
> > > For: VIZ-4636
> > > Signed-off-by: Jeff McGee <jeff.mcgee@intel.com>
> > > ---
> > >  drivers/gpu/drm/i915/i915_dma.c | 10 ++++++++++
> > >  include/uapi/drm/i915_drm.h     |  2 ++
> > >  2 files changed, 12 insertions(+)
> > >
> > > diff --git a/drivers/gpu/drm/i915/i915_dma.c
> > > b/drivers/gpu/drm/i915/i915_dma.c index 053e178..9350ea2 100644
> > > --- a/drivers/gpu/drm/i915/i915_dma.c
> > > +++ b/drivers/gpu/drm/i915/i915_dma.c
> > > @@ -150,6 +150,16 @@ static int i915_getparam(struct drm_device *dev,
> void *data,
> > >  	case I915_PARAM_MMAP_VERSION:
> > >  		value = 1;
> > >  		break;
> > > +	case I915_PARAM_SUBSLICE_TOTAL:
> > > +		value = INTEL_INFO(dev)->subslice_total;
> > > +		if (!value)
> > > +			return -ENODEV;
> > > +		break;
> > > +	case I915_PARAM_EU_TOTAL:
> > > +		value = INTEL_INFO(dev)->eu_total;
> > > +		if (!value)
> > > +			return -ENODEV;
> > > +		break;
> > >  	default:
> > >  		DRM_DEBUG("Unknown parameter %d\n", param->param);
> > >  		return -EINVAL;
> > > diff --git a/include/uapi/drm/i915_drm.h
> > > b/include/uapi/drm/i915_drm.h index 6eed16b..8672efc 100644
> > > --- a/include/uapi/drm/i915_drm.h
> > > +++ b/include/uapi/drm/i915_drm.h
> > > @@ -347,6 +347,8 @@ typedef struct drm_i915_irq_wait {  #define
> > > I915_PARAM_HAS_COHERENT_PHYS_GTT 29
> > >  #define I915_PARAM_MMAP_VERSION          30
> > >  #define I915_PARAM_HAS_BSD2		 31
> > > +#define I915_PARAM_SUBSLICE_TOTAL	 32
> > > +#define I915_PARAM_EU_TOTAL		 33
> > >
> > >  typedef struct drm_i915_getparam {
> > >  	int param;
> > > --
> > > 2.3.0
> > >
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