Messages in this thread | | | Date | Wed, 15 Dec 2021 18:27:40 +0100 | From | Mikhail Golubev <> | Subject | Re: [RFC PATCH] virtio: do not reset stateful devices on resume |
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The 12/14/2021 18:26, Michael S. Tsirkin wrote: > On Tue, Dec 14, 2021 at 05:33:05PM +0100, Mikhail Golubev wrote: > > From: Anton Yakovlev <Anton.Yakovlev@opensynergy.com> > > > > We assume that stateful devices can maintain their state while > > suspended. And for this reason they don't have a freeze callback. If > > such a device is reset during resume, the device state/context will be > > lost on the device side. And the virtual device will stop working. > > > > Signed-off-by: Anton Yakovlev <Anton.Yakovlev@opensynergy.com> > > Signed-off-by: Mikhail Golubev <mikhail.golubev@opensynergy.com> > > A bit more specific? Which configs does this patch fix?
We had encountered an issue related to 'stateful' GPU 3d (virglrenderer) and video (gstreamer) devices.
BR, Mikhail
> > > --- > > drivers/virtio/virtio.c | 8 ++++++++ > > 1 file changed, 8 insertions(+) > > > > diff --git a/drivers/virtio/virtio.c b/drivers/virtio/virtio.c > > index 236081afe9a2..defa15b56eb8 100644 > > --- a/drivers/virtio/virtio.c > > +++ b/drivers/virtio/virtio.c > > @@ -472,6 +472,13 @@ int virtio_device_restore(struct virtio_device *dev) > > struct virtio_driver *drv = drv_to_virtio(dev->dev.driver); > > int ret; > > > > + /* Short path for stateful devices. Here we assume that if the device > > + * does not have a freeze callback, its state was not changed when > > + * suspended. > > + */ > > + if (drv && !drv->freeze) > > + goto on_config_enable; > > + > > /* We always start by resetting the device, in case a previous > > * driver messed it up. */ > > dev->config->reset(dev); > > @@ -503,6 +510,7 @@ int virtio_device_restore(struct virtio_device *dev) > > /* Finally, tell the device we're all set */ > > virtio_add_status(dev, VIRTIO_CONFIG_S_DRIVER_OK); > > > > +on_config_enable: > > virtio_config_enable(dev); > > > > return 0; > > -- > > 2.34.1 > > > > > > -- >
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