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

[Joonas Lahtinen]

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.

Regards, Joonas
-- 
Joonas Lahtinen
Open Source Technology Center
Intel Corporation