Re: [PATCH v10] vfio: ABI for mdev display dma-buf operation

From	Gerd Hoffmann <kraxel@redhat.com>
Newsgroups	linux.kernel
Subject	Re: [PATCH v10] vfio: ABI for mdev display dma-buf operation
Date	2017-07-19 08:30 +0200
Message-ID	<u4QEF-4FE-17@gated-at.bofh.it> (permalink)
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On Wed, 2017-07-19 at 00:16 +0000, Zhang, Tina wrote:
> > -----Original Message-----
> > From: Gerd Hoffmann [mailto:kraxel@redhat.com]
> > Sent: Monday, July 17, 2017 7:03 PM
> > To: Kirti Wankhede <kwankhede@nvidia.com>; Zhang, Tina
> > <tina.zhang@intel.com>; Tian, Kevin <kevin.tian@intel.com>; linux-
> > kernel@vger.kernel.org; intel-gfx@lists.freedesktop.org;
> > alex.williamson@redhat.com; zhenyuw@linux.intel.com; chris@chris-
> > wilson.co.uk; Lv, Zhiyuan <zhiyuan.lv@intel.com>; intel-gvt-
> > dev@lists.freedesktop.org; Wang, Zhi A <zhi.a.wang@intel.com>
> > Subject: Re: [PATCH v10] vfio: ABI for mdev display dma-buf
> > operation
> > 
> >   Hi,
> > 
> > > No need of flag here. If vGPU driver is not loaded in the guest,
> > > there
> > > is no surface being managed by vGPU, in that case this size will
> > > be
> > > zero.
> > 
> > Ok, we certainly have the same situation with intel.  When the
> > guest driver is not
> > loaded (yet) there is no valid surface.
> > 
> > We should cleanly define what the ioctl should do in that case, so
> > all drivers
> > behave the same way.
> > 
> > I'd suggest that all fields defining the surface (drm_format,
> > width, height, stride,
> > size) should be set to zero in that case.
> 
> Yeah, it's reasonable. How about the return value? Currently, the
> ioctl also returns "-ENODEV" in that situation.

I think it should not return an error.  Querying the plane parameters
worked fine.

cheers,
  Gerd

Thread

RE: [PATCH v10] vfio: ABI for mdev display dma-buf operation "Zhang, Tina" <tina.zhang@intel.com> - 2017-07-19 02:20 +0200
  Re: [PATCH v10] vfio: ABI for mdev display dma-buf operation Gerd Hoffmann <kraxel@redhat.com> - 2017-07-19 08:30 +0200
    Re: [PATCH v10] vfio: ABI for mdev display dma-buf operation Kirti Wankhede <kwankhede@nvidia.com> - 2017-07-19 14:00 +0200

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