> From: Chen, Jiqian <jiqian.c...@amd.com> > Sent: Wednesday, September 20, 2023 12:03 PM
> If driver write 0 to reset device, can the SUSPEND bit be cleared? It must as reset operation, resets everything else and so the suspend too. > (pci_pm_resume->virtio_pci_restore->virtio_device_restore- > >virtio_reset_device) > If SUSPEND is cleared, then during the reset process in Qemu, I can't judge if > the reset request is from guest restore process or not, and then I can't > change > the reset behavior. Reset should not be influenced by suspend. Suspend should do the work of suspend and reset to do the reset. The problem to overcome in [1] is, resume operation needs to be synchronous as it involves large part of context to resume back, and hence just asynchronously setting DRIVER_OK is not enough. The sw must verify back that device has resumed the operation and ready to answer requests. This is slightly different flow than setting the DRIVER_OK for the first time device initialization sequence as it does not involve large restoration. So, to merge two ideas, instead of doing DRIVER_OK to resume, the driver should clear the SUSPEND bit and verify that it is out of SUSPEND. Because driver is still in _OK_ driving the device flipping the SUSPEND bit.
