Messages in this thread | | | Date | Fri, 23 Jun 2017 11:15:54 -0600 | From | Alex Williamson <> | Subject | Re: [Intel-gfx] [PATCH v9 5/7] vfio: Define vfio based dma-buf operations |
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On Fri, 23 Jun 2017 09:26:59 +0200 Gerd Hoffmann <kraxel@redhat.com> wrote:
> Hi, > > > Is this only going to support accelerated driver output, not basic > > VGA > > modes for BIOS interaction? > > Right now there is no vgabios or uefi support for the vgpu. > > But even with that in place there still is the problem that the display > device initialization happens before the guest runs and therefore there > isn't an plane yet ... > > > > Right now the experimental intel patches throw errors in case no > > > plane > > > exists (yet). Maybe we should have a "bool is_enabled" field in > > > the > > > plane_info struct, so drivers can use that to signal whenever the > > > guest > > > has programmed a valid video mode or not (likewise for the cursor, > > > which doesn't exist with fbcon, only when running xorg). With that > > > in > > > place using the QUERY_PLANE ioctl also for probing looks > > > reasonable. > > > > Sure, or -ENOTTY for ioctl not implemented vs -EINVAL for no > > available > > plane, but then that might not help the user know how a plane would > > be > > available if it were available. > > So maybe a "enum plane_state" (instead of "bool is_enabled")? So we > can clearly disturgish ENABLED, DISABLED, NOT_SUPPORTED cases?
What's the difference between NOT_SUPPORTED and -ENOTTY on the ioctl? Perhaps a bit in a flags field could specify EN/DIS-ABLED and leave room for things we're forgetting. Keep in mind that we need to use explicit width fields for a uapi structure, so __u32 vs enum. Thanks,
Alex
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