Hi,
Randy Dunlap <rdunlap@xxxxxxxxxxxxx> writes:
> Linux v5.0-11053-gebc551f2b8f9 of March 12, on x86_64:
>
> with
> CONFIG_USB_G_DBGP=m
> # CONFIG_USB_G_DBGP_PRINTK is not set
> CONFIG_USB_G_DBGP_SERIAL=y
> CONFIG_USB_U_SERIAL=m
>
> Loading g_dbgp module and then unloading it causes:
>
> WARNING: CPU: 0 PID: 24523 at ../drivers/usb/gadget/function/u_serial.c:1195 gserial_free_line+0x161/0x2b0 [u_serial]
>
>
> Is that expected?
Not really, but I tried reproducing this here and couldn't get the same
behavior. In fact, I can't see how that driver can work without a
configuration descriptor. Here are all descriptor defined by the driver:
36:static struct usb_device_descriptor device_desc = {
46:static struct usb_debug_descriptor dbg_desc = {
51:static struct usb_endpoint_descriptor i_desc = {
58:static struct usb_endpoint_descriptor o_desc = {
And here's an excerpt of the setup function:
static int dbgp_setup(struct usb_gadget *gadget,
const struct usb_ctrlrequest *ctrl)
{
struct usb_request *req = dbgp.req;
u8 request = ctrl->bRequest;
u16 value = le16_to_cpu(ctrl->wValue);
u16 length = le16_to_cpu(ctrl->wLength);
int err = -EOPNOTSUPP;
void *data = NULL;
u16 len = 0;
if (request == USB_REQ_GET_DESCRIPTOR) {
switch (value>>8) {
case USB_DT_DEVICE:
dev_dbg(&dbgp.gadget->dev, "setup: desc device\n");
len = sizeof device_desc;
data = &device_desc;
device_desc.bMaxPacketSize0 = gadget->ep0->maxpacket;
break;
case USB_DT_DEBUG:
dev_dbg(&dbgp.gadget->dev, "setup: desc debug\n");
len = sizeof dbg_desc;
data = &dbg_desc;
break;
default:
goto fail;
}
err = 0;
} else if (request == USB_REQ_SET_FEATURE &&
value == USB_DEVICE_DEBUG_MODE) {
dev_dbg(&dbgp.gadget->dev, "setup: feat debug\n");
#ifdef CONFIG_USB_G_DBGP_PRINTK
err = dbgp_enable_ep();
#else
err = dbgp_configure_endpoints(gadget);
if (err < 0) {
goto fail;
}
err = gserial_connect(dbgp.serial, tty_line);
#endif
if (err < 0)
goto fail;
} else
goto fail;
It always stalls GetDescriptor(Configuration) requests. It's also
missing interface descriptors. What gives? How can that work?
Anybody has a specification for how this class is supposed to work? I
suppose this is EHCI-specific?
--
balbi
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