Commit 56626a72 authored Oct 14, 2010 by Alan Stern Committed by Greg Kroah-Hartman Oct 22, 2010

USB: accept some invalid ep0-maxpacket values



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@rowland.harvard.edu>
Reported-by: James <bjlockie@lockie.ca>
Cc: stable <stable@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

parent 5535b1d5

drivers/usb/core/hub.c

+6 −3

Original line number	Diff line number	Diff line
		@@ -2861,13 +2861,16 @@ hub_port_init (struct usb_hub hub, struct usb_device udev, int port1,
		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;
		}
		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);
		}

Admin message