On Thu, 22 Feb 2018 15:46:17 +0000 Peter Maydell <peter.mayd...@linaro.org> wrote:
> On 22 February 2018 at 15:37, Gerd Hoffmann <kra...@redhat.com> wrote: > > On Mon, Feb 19, 2018 at 12:14:55PM +0100, Gerd Hoffmann wrote: > >> vfio display support wants disable hotplug for certain devices, because > >> qemu doesn't support hotplugging display devices and qemu consoles. > >> > >> Add a hotpluggable bool to DeviceState, initialize it from > >> DeviceClass->hotpluggable, update device_get_hotpluggable accordingly. > >> > >> Devices can flip the new variable from true to false if needed. > > > > Alex wants an ack for this one. Who maintains it these days? > > > > MAINTAINERS doesn't list qdev. For QOM which is closest probably > > Andreas Färber is listed. Havn't seen him on the list for a while > > though. > > > > Ok, lets try some usual suspects... > > Markus? Eric? Paolo? Peter? Any comments on this one? > > What type of device is only sometimes hotpluggable ? > The commit message says "display devices" and "consoles", > but I would expect those to both be types of device which > have a class which is never hotpluggable, so you can mark > them non-hotpluggable with the existing class flag rather > than needing a per-instance flag. With this series, a vfio-pci device optionally supports a display. The vfio-pci device is hotpluggable, but QEMU display support is not. So the solution here is to make the vfio-pci device non-hotpluggable only when it supports and enables a display. Gerd, is there another solution that the display object is instantiated separately from the vfio-pci object and the display support in the vfio-pci device references the display object via an id. Possibly vfio-pci could remain hotpluggable while the display class device is not. Potentially one display could be switched between multiple display capable devices, like an input control button on a monitor, losing signal if none are connected. Possible? Clearly I have no idea how display objects actually work in QEMU. Thanks, Alex
