A few devices (such as the RCA VR5220 voice recorder) are so
non-compliant with the USB spec that they have invalid maxpacket sizes
for endpoint 0. Nevertheless, as long as we can safely use them, we
may as well do so.
This patch (as1432) softens our acceptance criterion by allowing
high-speed devices to have ep0-maxpacket sizes other than 64. A
warning is printed in the system log when this happens, and the
existing error message is clarified.
Signed-off-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>
Reported-by: James <bjlockie@xxxxxxxxx>
---
Greg:
This doesn't fix a bug, since the device in question is not compliant
with the spec. On the other hand I don't see how it could introduce
any poblems, and Windows already works with this device.
It's up to you whether or not to queue this for the -stable kernels.
Alan Stern
Index: usb-2.6/drivers/usb/core/hub.c
===================================================================
--- usb-2.6.orig/drivers/usb/core/hub.c
+++ usb-2.6/drivers/usb/core/hub.c
@@ -2882,13 +2882,16 @@ hub_port_init (struct usb_hub *hub, stru
else
i = udev->descriptor.bMaxPacketSize0;
if (le16_to_cpu(udev->ep0.desc.wMaxPacketSize) != i) {
- if (udev->speed != USB_SPEED_FULL ||
+ if (udev->speed == USB_SPEED_LOW ||
!(i == 8 || i == 16 || i == 32 || i == 64)) {
- dev_err(&udev->dev, "ep0 maxpacket = %d\n", i);
+ dev_err(&udev->dev, "Invalid ep0 maxpacket: %d\n", i);
retval = -EMSGSIZE;
goto fail;
}
- dev_dbg(&udev->dev, "ep0 maxpacket = %d\n", i);
+ if (udev->speed == USB_SPEED_FULL)
+ dev_dbg(&udev->dev, "ep0 maxpacket = %d\n", i);
+ else
+ dev_warn(&udev->dev, "Using ep0 maxpacket: %d\n", i);
udev->ep0.desc.wMaxPacketSize = cpu_to_le16(i);
usb_ep0_reinit(udev);
}
--
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