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USB: accept some invalid ep0-maxpacket values

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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>
This commit is contained in:
Alan Stern 2010-10-14 15:25:21 -04:00 committed by Greg Kroah-Hartman
parent 5535b1d5f8
commit 56626a72a4
1 changed files with 6 additions and 3 deletions
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9
drivers/usb/core/hub.c
View file

@ -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;
}
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);
}