| Message ID | 1306834530-12763-8-git-send-email-hdegoede@redhat.com |
|---|---|
| State | New |
| Headers | show |
On 05/31/11 11:35, Hans de Goede wrote: > So that we don't retry to open it every 2 seconds flooding stderr with > error messages. The polling here is done intentionally, so the devices catched by the filter show up in the guest automagically as soon as they are plugged in. Just zapping the filter on failure isn't the right thing to do here. We could try to do something more clever than polling sysfs every two seconds though, such using inotify to watch /sys/bus/usb/devices for new devices poping up. cheers, Gerd
Hi, On 06/01/2011 02:32 PM, Gerd Hoffmann wrote: > On 05/31/11 11:35, Hans de Goede wrote: >> So that we don't retry to open it every 2 seconds flooding stderr with >> error messages. > > The polling here is done intentionally, so the devices catched by the filter show up in the guest automagically as soon as they are plugged in. Just zapping the filter on failure isn't the right thing to do here. Note I'm zapping the filter when we fail to open the device, not when it is not present. This can happen for example when the qemu user does not have rights on the usbfs device node. It seems better to me to print the relevant error once, and then require the user to redo the usb_add / device_add if necessary, then to flood the monitor with repeating the same error every 2 seconds. Note that something like a permission problem (which is the most likely case for opening a device failing once we've found it) won't go away by itself. > We could try to do something more clever than polling sysfs every two seconds though, such using inotify to watch /sys/bus/usb/devices for new devices poping up. That would also result in trying to open the device ones, and if that fails give up, I don't see the difference. Actually the user experience would be worse, because the proper sequence in case of a permission problem would go from: usb_add see error fix permission usb_add to: usb_add see error fix permission usb_del usb_add Regards, Hans
On 06/01/11 16:37, Hans de Goede wrote: > Hi, > > On 06/01/2011 02:32 PM, Gerd Hoffmann wrote: >> On 05/31/11 11:35, Hans de Goede wrote: >>> So that we don't retry to open it every 2 seconds flooding stderr with >>> error messages. >> >> The polling here is done intentionally, so the devices catched by the >> filter show up in the guest automagically as soon as they are plugged >> in. Just zapping the filter on failure isn't the right thing to do here. > > Note I'm zapping the filter when we fail to open the device, not when it > is not present. This can happen for example when the qemu user does not > have rights on the usbfs device node. > > It seems better to me to print the relevant error once, and then require > the user to redo the usb_add / device_add if necessary, then to flood > the monitor with repeating the same error every 2 seconds. Devices magically disappearing is a problem for the management stack (such as libvirt) though. qemu does stuff like that in too many places already and we are trying to get rid of it. Flooding the monitor (or stderr) indeed isn't nice though. cheers, Gerd
diff --git a/usb-linux.c b/usb-linux.c index e2f45d3..334012e 100644 --- a/usb-linux.c +++ b/usb-linux.c @@ -122,6 +122,7 @@ typedef struct USBHostDevice { int configuration; int ninterfaces; int closing; + int open_failed; Notifier exit; struct endp_data endp_table[MAX_ENDPOINTS]; @@ -1208,6 +1209,10 @@ static int usb_host_initfn(USBDevice *dev) s->exit.notify = usb_host_exit_notifier; qemu_add_exit_notifier(&s->exit); usb_host_auto_check(NULL); + if (s->open_failed) { + usb_host_handle_destroy(dev); + return s->open_failed; + } return 0; } @@ -1272,7 +1277,11 @@ USBDevice *usb_host_device_open(const char *devname) qdev_prop_set_uint32(&dev->qdev, "hostaddr", filter.addr); qdev_prop_set_uint32(&dev->qdev, "vendorid", filter.vendor_id); qdev_prop_set_uint32(&dev->qdev, "productid", filter.product_id); - qdev_init_nofail(&dev->qdev); + + if (qdev_init(&dev->qdev) != 0) { + return NULL; + } + return dev; fail: @@ -1637,6 +1646,7 @@ static int usb_host_auto_scan(void *opaque, int bus_num, int addr, char *port, { struct USBAutoFilter *f; struct USBHostDevice *s; + int ret; /* Ignore hubs */ if (class_id == 9) @@ -1670,7 +1680,15 @@ static int usb_host_auto_scan(void *opaque, int bus_num, int addr, char *port, } DPRINTF("husb: auto open: bus_num %d addr %d\n", bus_num, addr); - usb_host_open(s, bus_num, addr, port, product_name, speed); + ret = usb_host_open(s, bus_num, addr, port, product_name, speed); + if (ret) { + /* If we've found a match but failed to open the device we should + remove it from our auto-filter list, so we don't keep trying to + open it every 2 seconds. However we cannot destroy / free it + here, since we get called from usb_host_initfn, and destroying + a qdev from its initfn is not allowed. */ + s->open_failed = ret; + } } return 0; @@ -1678,9 +1696,16 @@ static int usb_host_auto_scan(void *opaque, int bus_num, int addr, char *port, static void usb_host_auto_check(void *unused) { - struct USBHostDevice *s; + struct USBHostDevice *s, *n; int unconnected = 0; + /* Cleanup devices wich failed to open last time, see usb_host_auto_scan + for why we don't do this after usb_host_auto_scan */ + QTAILQ_FOREACH_SAFE(s, &hostdevs, next, n) { + if (s->open_failed) + qdev_free(&s->dev.qdev); + } + usb_host_scan(NULL, usb_host_auto_scan); QTAILQ_FOREACH(s, &hostdevs, next) {