Hi Alan, Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> schrieb: > On Mon, 23 Sep 2013, Kurt Garloff wrote: > > > >> that qualifies as a bug or not. Maybe it should not claim to be a > > >> HID device then? > > > Maybe not. This particular combination of bRequestType and > bRequest > > > values (0x22, 0x09) is not defined in the HID 1.11 spec. Do you > know > > > if it is defined somewhere else? > > These are custom commands, somewhat described at > > > http://pegatech.com/_Uploads/Downloads/Documents/Protocol_Definition_Rev_1.12.pdf > > That document describes a UART protocol with no mention of USB at all. Yep, probably they just took the serial protocol to USB... Beyond the spec, I did watch the Win app a bit when implementing [2] ... > > With behavior here I referred to the fact that I have not yet seen a > USB > > device that > > has two endpoints with the same endpoint number (but different direction). > > I have. They aren't very common but they do exist. > > > Let me try inline insert (by c'n'p: I switched from mutt to Thunderbird > > recently and lack > > experience whether this breaks formatting or so ...) > > It did mangle the whitespace characters. Cr*p. > That doesn't matter for > reviewing, but it is important when you submit the patch. Take a look > > at Documentation/email-clients.txt for some suggestions. I'll go back to mutt then, I guess - used it for >10 years... > > 8<-------- > > > > From: Kurt Garloff <kurt@xxxxxxxxxx> > > Date: Mon, 23 Sep 2013 14:19:02 +0200 > > Subject: Tolerate wrong direction bit in endpoint address for control > > messages > > > > Trying to read data from the Pegasus Technologies NoteTaker (0e20:0101) > > [1] with the Windows App (EasyNote) works natively but fails when > > Windows is running under KVM (and the USB device handed to KVM). > > > > The reason is a USB control message > > usb 4-2.2: control urb: bRequestType=22 bRequest=09 wValue=0200 > > wIndex=0001 wLength=0008 > > This goes to endpoint address 0x01 (wIndex); however, endpoint number 1 > > is an input endpoint and thus has endpoint address 0x81. > > You should say something like: > > however, endpoint 0x01 doesn't exist. There is an endpoint > 0x81, though; perhaps the app meant that endpoint instead. OK. > > The kernel thus rejects the IO and thus we see the failure. > > > > Apparently, Linux is more strict here than Windows ... we can't change > > the Win app easily, so that's a problem. > > > > It seems that the Win app/driver is buggy here and the driver does not > > behave fully according to the USB HID class that it claims to belong to. > > The device seems to happily deal with that though (and seems to not > > really care about this value much). > > > > So the question is whether the Linux kernel should filter here. > > Rejecting has the risk that somewhat non-compliant userspace apps/ > > drivers (most likely in a virtual machine) are prevented from > working. > > Not rejecting has the risk of confusing an overly sensitive device with > > such a transfer. Given the fact that Windows does not filter it makes > > this risk rather small though. > > > > The patch makes the kernel more tolerant: If the endpoint address in > > wIndex does not exist, but an endpoint with toggled direction bit does, > > it will let the transfer through. (It does NOT change the message.) > > > > With attached patch, the app in Windows in KVM works. > > usb 4-2.2: check_ctrlrecip: process 13073 (qemu-kvm) requesting ep > 01 > > but needs 81 (or 00) > > You need to remove the "(or 00)" here. Good catch! I changed the code but not the log... > > I suspect this will mostly affect apps in virtual environments; as on > > Linux the apps would have been adapted to the stricter handling of the > > kernel. I have done that for mine[2]. > > > > [1] http://www.pegatech.com/ > > [2] https://sourceforge.net/projects/notetakerpen/ > > > > Signed-off-by: Kurt Garloff <kurt@xxxxxxxxxx> > > Cc: stable@xxxxxxxxxxxxxx > > Fix the spelling (.org). The second time in two days, my fingers are getting too slow... > > --- > > drivers/usb/core/devio.c | 16 ++++++++++++++++ > > 1 file changed, 16 insertions(+) > > > > diff --git a/drivers/usb/core/devio.c b/drivers/usb/core/devio.c > > index 737e3c1..4ff61f9 100644 > > --- a/drivers/usb/core/devio.c > > +++ b/drivers/usb/core/devio.c > > @@ -742,6 +742,22 @@ static int check_ctrlrecip(struct dev_state *ps, > > unsigned int requesttype, > > if ((index & ~USB_DIR_IN) == 0) > > return 0; > > ret = findintfep(ps->dev, index); > > + if (ret < 0) { > > + /* > > + * Some not fully compliant Win apps seem to get > > + * ndex wrong and have the endpoint number here > > s/ndex/index/ Thx. > > > + * rather than the endpoint address (with the > > + * correct direction). Win does let this through, > > + * so we'll give it a second try as well (to not > > + * break KVM) -- but warn. > > + */ > > + ret = findintfep(ps->dev, index ^ 0x80); > > + if (ret >= 0) > > + dev_info(&ps->dev->dev , > > + "%s: process %i (%s) requesting ep %02x but > needs > > %02x\n", > > + __func__, task_pid_nr(current), > > + current->comm, index, index ^ 0x80); > > + } > > if (ret >= 0) > > ret = checkintf(ps, ret); > > break; > > After you make these changes, you can add: > > Acked-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> Thank you, will do that! And thanks for all your support. -- Kurt Garloff <kurt@xxxxxxxxxx> (Sent from Android Phone with K-9 Mail.) -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
