On Fri, 7 Sep 2018 16:05:15 +0200 Gerd Hoffmann <kraxel@xxxxxxxxxx> 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. > > 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 > > RfC patch for the vfio interface is below. > > Comments? > > cheers, > Gerd > > =================== cut here =================== > > From 556299e8c6280b1c4061fdae15491a013c22be98 Mon Sep 17 00:00:00 2001 > From: Gerd Hoffmann <kraxel@xxxxxxxxxx> > Date: Thu, 6 Sep 2018 16:17:17 +0200 > Subject: [PATCH] [RfC] vfio: edid interface > > Signed-off-by: Gerd Hoffmann <kraxel@xxxxxxxxxx> > --- > include/uapi/linux/vfio.h | 42 ++++++++++++++++++++++++++++++++++++++++++ > 1 file changed, 42 insertions(+) > > diff --git a/include/uapi/linux/vfio.h b/include/uapi/linux/vfio.h > index 1aa7b82e81..9ac7dfb7c1 100644 > --- a/include/uapi/linux/vfio.h > +++ b/include/uapi/linux/vfio.h > @@ -602,6 +602,48 @@ struct vfio_device_ioeventfd { > > #define VFIO_DEVICE_IOEVENTFD _IO(VFIO_TYPE, VFIO_BASE + 16) > > +/** > + * VFIO_DEVICE_GFX_EDID_CAPS - _IOW(VFIO_TYPE, VFIO_BASE + 17, > + * struct vfio_device_gfx_edid_caps) We haven't been very consistent with the _IOW vs _IOR vs _IOWR and as a comment it's obviously not enforced, only meant to convey the nature of the ioctl, but _IOW is probably the one choice that least matches. We have other examples of using _IOR (ignoring that argsz is passed in) and _IOWR, which is technically more accurate. Looks like we missed this for the other GFX ioctls as well. I'd prefer to see "GET" in the ioctl name as well, perhaps VFIO_DEVICE_GET_GFX_EDID_CAPS. Is this really EDID when it's only the resolution though? > + * > + * Get edid capabilities. > + * > + * Drivers must support either none or both GFX_EDID ioctls, > + * so the CAPS ioctl can also be used to probe for edid support. > + * > + * max_xres, max_yres - maximum display resolution supported. > + * value "0" means no restriction. > + * > + */ > +struct vfio_device_gfx_edid_caps { > + __u32 argsz; > + __u32 flags; > + /* out */ > + __u32 max_xres; > + __u32 max_yres; > +}; > + > +#define VFIO_DEVICE_GFX_EDID_CAPS _IO(VFIO_TYPE, VFIO_BASE + 17) > + > +/** > + * VFIO_DEVICE_GFX_EDID_SET - _IOW(VFIO_TYPE, VFIO_BASE + 18, > + * struct vfio_device_gfx_edid_set) Perhaps flip this around, VFIO_DEVICE_SET_GFX_EDID. > + * > + * 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]; Is the format of this blob defined somewhere? Can we provide a reference here to that format? Thanks, Alex > +}; > + > +#define VFIO_DEVICE_GFX_EDID_SET _IO(VFIO_TYPE, VFIO_BASE + 18) > + > /* -------- API for Type1 VFIO IOMMU -------- */ > > /**
