From: Zhenyu Wang <zhenyuw@linux.intel.com>
To: Gerd Hoffmann <kraxel@redhat.com>
Cc: Alex Williamson <alex.williamson@redhat.com>,
Kirti Wankhede <kwankhede@nvidia.com>,
intel-gvt-dev@lists.freedesktop.org,
open list <linux-kernel@vger.kernel.org>,
kvm@vger.kernel.org
Subject: Re: [PATCH 1/2] vfio: add edid api for display (vgpu) devices.
Date: Mon, 17 Sep 2018 17:15:50 +0800 [thread overview]
Message-ID: <20180917091550.GK20737@zhen-hp.sh.intel.com> (raw)
In-Reply-To: <20180917085033.ttcs3cpznnf3wngd@sirius.home.kraxel.org>
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On 2018.09.17 10:50:33 +0200, Gerd Hoffmann wrote:
> > > +#define VFIO_DEVICE_INFO_CAP_EDID 1
> > > +
> > > +struct vfio_device_info_edid_cap {
> > > + struct vfio_info_cap_header header;
> > > + __u32 max_x; /* Max display height (zero == no limit) */
> > > + __u32 max_y; /* Max display height (zero == no limit) */
> > > +};
> >
> > As current virtual display for Intel vGPU is still emulating against real HW
> > pipeline with same limitations, asked display developers that whether or not
> > specific mode can work might still depend on current or future HW behavior.
> > So could we add some hints on what kind of edid mode vfio device can operate?
> > Some may support arbitrary modes, but some may only support standard modes.
>
> What kind of restrictions do we have here? Really to a fixed list of
> standard modes?
Restriction is still with HW differences, e.g for skl/kbl with ddi wrpll
within min/max clock range which may generate any required frequency, but
I've been told for bxt there're some gaps in clock range that could be
generated.
>
> Some testing (kaby lake) indicates y axis has no restrictions and x axis
> gets rounded up to the next multiple of 8 pixels (32 bytes), maybe to
> align scanlines with cachelines?
That should be plane stride requirement I think.
>
> Oh, and btw: Seems the resolution restriction (to 1024x768 for the
> smallest vgpu type) seems to not be enforced. Intentional?
>
hmm, what do you mean here? Not enforce to have only one mode for vgpu type?
Or can't change to other mode?
--
Open Source Technology Center, Intel ltd.
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next prev parent reply other threads:[~2018-09-17 9:26 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20180913054745.6353-1-kraxel@redhat.com>
2018-09-13 5:47 ` [PATCH 1/2] vfio: add edid api for display (vgpu) devices Gerd Hoffmann
2018-09-13 17:51 ` Alex Williamson
2018-09-14 12:25 ` Gerd Hoffmann
2018-09-14 15:31 ` Alex Williamson
2018-09-17 6:51 ` Zhenyu Wang
2018-09-17 8:50 ` Gerd Hoffmann
2018-09-17 9:15 ` Zhenyu Wang [this message]
2018-09-17 10:13 ` Gerd Hoffmann
2018-09-13 5:47 ` [PATCH 2/2] vfio: add edid support to mbochs sample driver Gerd Hoffmann
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