[Intel-gfx] [PATCH v2] drm/i915/gvt: disable GVT-g if host GuC submission is enabled

[Dong, Chuanxiao]

> -----Original Message-----
> From: Joonas Lahtinen [mailto:joonas.lahtinen at linux.intel.com]
> Sent: Thursday, May 11, 2017 8:50 PM
> To: Dong, Chuanxiao <chuanxiao.dong at intel.com>; intel-gvt-
> dev at lists.freedesktop.org; intel-gfx at lists.freedesktop.org
> Subject: Re: [Intel-gfx] [PATCH v2] drm/i915/gvt: disable GVT-g if host GuC
> submission is enabled
> 
> On to, 2017-05-11 at 02:33 +0000, Dong, Chuanxiao wrote:
> >
> > >
> > > -----Original Message-----
> > > From: Joonas Lahtinen [mailto:joonas.lahtinen at linux.intel.com]
> > > Sent: Wednesday, May 10, 2017 8:48 PM
> > > To: Dong, Chuanxiao <chuanxiao.dong at intel.com>; intel-gvt-
> > > dev at lists.freedesktop.org; intel-gfx at lists.freedesktop.org
> > > Subject: Re: [Intel-gfx] [PATCH v2] drm/i915/gvt: disable GVT-g if
> > > host GuC submission is enabled
> > >
> > > On ti, 2017-05-09 at 18:11 +0800, Chuanxiao Dong wrote:
> > > >
> > > > Currently GVT-g cannot work properly when host GuC submission is
> > > > enabled, so disable GVT in this case.
> > > >
> > > > v2: update the user message (Joonas)
> > > >
> > > > > > > Cc: Zhenyu Wang <zhenyuw at linux.intel.com>
> > > > > > > Signed-off-by: Chuanxiao Dong <chuanxiao.dong at intel.com>
> > > > ---
> > > >  drivers/gpu/drm/i915/intel_gvt.c | 5 +++++
> > > >  1 file changed, 5 insertions(+)
> > > >
> > > > diff --git a/drivers/gpu/drm/i915/intel_gvt.c
> > > > b/drivers/gpu/drm/i915/intel_gvt.c
> > > > index e1ab643..d85742c 100644
> > > > --- a/drivers/gpu/drm/i915/intel_gvt.c
> > > > +++ b/drivers/gpu/drm/i915/intel_gvt.c
> > > > @@ -84,6 +84,11 @@ int intel_gvt_init(struct drm_i915_private
> *dev_priv)
> > > >  		goto bail;
> > > >  	}
> > > >
> > > > +	if (i915.enable_guc_submission) {
> > > > +		DRM_INFO("GPU guest virtualisation [GVT-g] disabled as
> > > Graphics virtualization is not yet supported with GuC submission
> > > [i915.enable_guc_submission module parameter]\n");
> > > >
> > > > +		goto bail;
> > > > +	}
> > >
> > > As discussed earlier, driver loading should fail with -EIO when
> > > incompatible options are specified.
> >
> > Sorry for not getting why should fail with -EIO? By looking into the
> > source, Intel_gvt_init is part of i915 driver loading, and fail with
> > -EIO will make i915 driver failed to load.
> 
> Yes, the user has specified an unsafe kernel configuration option,
> enable_guc_submission and the driver can rightfully stop loading if
> enable_gvt option was passed in the same command line.
> 
Thanks Joonas. If to fail with -EIO, how about for the other two checks: " if (!is_supported_device(dev_priv))" and " if (!i915.enable_execlists)"?  Currently these two cases are failed with 0 instead of -EIO. Looks like should also fail with -EIO?

For the gvt init failure case, it is also failed with 0 right now, which means that even gvt init is failed, i915 loading will be continue instead of failed due to gvt. Right now we also want to fail with -EIO, right?

Thanks
Chuanxiao