From 66007a95674d4b8e616245541faad6cdf5e9f70d Mon Sep 17 00:00:00 2001 From: Mark Cave-Ayland Date: Tue, 27 Oct 2020 15:04:54 +0000 Subject: dev-serial: add always-plugged property to ensure USB device is always attached 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 Reviewed-by: Samuel Thibault Message-id: 20201027150456.24606-7-mark.cave-ayland@ilande.co.uk Signed-off-by: Gerd Hoffmann --- hw/usb/dev-serial.c | 9 ++++++--- 1 file changed, 6 insertions(+), 3 deletions(-) (limited to 'hw/usb') diff --git a/hw/usb/dev-serial.c b/hw/usb/dev-serial.c index 92c35615eb..b9e308dca1 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(), }; -- cgit v1.2.3