Mark Cave-Ayland, le lun. 26 oct. 2020 08:33:58 +0000, a ecrit:
> Some operating systems will generate a new device ID when a USB device is unplugged
> and then replugged into the USB. If this is done whilst switching between multiple
> applications over a virtual serial port, the change of device ID requires going
> back into the OS/application to locate the new device accordingly.
>
> Add a new always-plugged property that if specified will ensure that the device
> always remains attached to the USB regardless of the state of the backend
> chardev.
>
> Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Reviewed-by: Samuel Thibault <samuel.thibault@ens-lyon.org>
> ---
> hw/usb/dev-serial.c | 9 ++++++---
> 1 file changed, 6 insertions(+), 3 deletions(-)
>
> diff --git a/hw/usb/dev-serial.c b/hw/usb/dev-serial.c
> index 92c35615eb..919e25e1d9 100644
> --- a/hw/usb/dev-serial.c
> +++ b/hw/usb/dev-serial.c
> @@ -97,6 +97,7 @@ struct USBSerialState {
> uint8_t event_chr;
> uint8_t error_chr;
> uint8_t event_trigger;
> + bool always_plugged;
> QEMUSerialSetParams params;
> int latency; /* ms */
> CharBackend cs;
> @@ -516,12 +517,12 @@ static void usb_serial_event(void *opaque, QEMUChrEvent event)
> s->event_trigger |= FTDI_BI;
> break;
> case CHR_EVENT_OPENED:
> - if (!s->dev.attached) {
> + if (!s->always_plugged && !s->dev.attached) {
> usb_device_attach(&s->dev, &error_abort);
> }
> break;
> case CHR_EVENT_CLOSED:
> - if (s->dev.attached) {
> + if (!s->always_plugged && s->dev.attached) {
> usb_device_detach(&s->dev);
> }
> break;
> @@ -556,7 +557,8 @@ static void usb_serial_realize(USBDevice *dev, Error **errp)
> usb_serial_event, NULL, s, NULL, true);
> usb_serial_handle_reset(dev);
>
> - if (qemu_chr_fe_backend_open(&s->cs) && !dev->attached) {
> + if (s->always_plugged || (qemu_chr_fe_backend_open(&s->cs) &&
> + !dev->attached)) {
> usb_device_attach(dev, &error_abort);
> }
> s->intr = usb_ep_get(dev, USB_TOKEN_IN, 1);
> @@ -584,6 +586,7 @@ static const VMStateDescription vmstate_usb_serial = {
>
> static Property serial_properties[] = {
> DEFINE_PROP_CHR("chardev", USBSerialState, cs),
> + DEFINE_PROP_BOOL("always-plugged", USBSerialState, always_plugged, false),
> DEFINE_PROP_END_OF_LIST(),
> };
>
> --
> 2.20.1
>
--
Samuel
"...[Linux's] capacity to talk via any medium except smoke signals."
(By Dr. Greg Wettstein, Roger Maris Cancer Center)