On 2018.09.07 16:05:15 +0200, Gerd Hoffmann wrote: > Hi, > > I consider adding EDID support to qemu, for display configuration. > > qemu patches are here: > https://git.kraxel.org/cgit/qemu/log/?h=sirius/edid > > linux kernel patches are here: > https://git.kraxel.org/cgit/linux/log/?h=edid > > Current (experimental) patches have support for the stdvga and > virtio-vga. > > I think it would be quite useful for vgpu too. Unlike emulated devices > vgpu's do not have a paravirtual display configuration path, because the > standard way to configure the display is to simply read the edid from > the monitor. > > Intel has two hard-coded edid blobs for that (depending on vgpu type). > Not sure how nvidia handles this, but probably simliar. With qemu > passing a edid blob for the virtual display instead of using the > hardcoded blob we could make the display configuration much more > flexible. > > Ideally qemu would also be able to update the edid blob at any time, and > the vgpu will notify the guest about it (probably by emulating a monitor > hotplug event). The guest can react on qemu window resizing then and > adapt automatically, simliar to how it works with qxl and virtio-gpu. What's the frequency for those edid update during resizing? Looks it's possible to bring hotplug storm that I'm not sure if all guest drivers for gvt has proper handling. > > The guest and the vgpu should be able to handle "odd" non-standard > display resolutions like this (coming from random window resizing): > > Detailed mode: Clock 106.620 MHz, 477 mm x 330 mm > 1212 1515 1551 1636 hborder 0 > 840 844 848 869 vborder 0 > -hsync -vsync > VertFreq: 74 Hz, HorFreq: 65171 Hz > Some odd timing might not be supported, e.g can't get a sane PLL setting calculation for clock required. As gvt exposes a virtual display pipeline following hw definition, so guest driver still depend on sane output, I think that may just go wrong with arbitrary mode.. > +/** > + * VFIO_DEVICE_GFX_EDID_SET - _IOW(VFIO_TYPE, VFIO_BASE + 18, > + * struct vfio_device_gfx_edid_set) > + * > + * Set edid blob. > + * > + * Should trigger monitor hotplug emulation, to notifiy the guest os > + * that the edid has changed. > + * > + */ > +struct vfio_device_gfx_edid_set { > + __u32 argsz; > + __u32 flags; > + /* in */ > + __u8 edid[256]; > +}; > + I assume you have defined return value for the set too right? In case for driver can't handle or invalid edid blob, etc. > +#define VFIO_DEVICE_GFX_EDID_SET _IO(VFIO_TYPE, VFIO_BASE + 18) > + > /* -------- API for Type1 VFIO IOMMU -------- */ > > /** > -- > 2.9.3 > > _______________________________________________ > intel-gvt-dev mailing list > intel-gvt-dev@xxxxxxxxxxxxxxxxxxxxx > https://lists.freedesktop.org/mailman/listinfo/intel-gvt-dev -- Open Source Technology Center, Intel ltd. $gpg --keyserver wwwkeys.pgp.net --recv-keys 4D781827
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