From: Micah Dowty <[EMAIL PROTECTED]>
This patch removes the artificial 4088-byte limit that usbfs
currently places on Control transfers. The USB spec does not
specify a strict limit on the size of an entire control transfer.
It does, however, state that the data stage "follows the same
protocol rules as bulk transfers." (USB 2, 8.5.3)
The level of support for large control transfers in real host
controllers varies, but it's important to support at least 4K
transfers. Windows enforces a maximum control transfer size
of 4K, so there exists some hardware that requires a full 4096
byte data stage. Without this patch, we fall short of that by
8 bytes on architectures with a 4K page size, and it becomes
impossible to support such hardware with a user-space driver.
Since any limit placed on control transfers by usbfs would be
arbitrary, this patch replaces the PAGE_SIZE limit with the same
arbitrary limit used by bulk transfers.
Signed-off-by: Micah Dowty <[EMAIL PROTECTED]>
Signed-off-by: Greg Kroah-Hartman <[EMAIL PROTECTED]>
---
drivers/usb/core/devio.c | 4 ++--
1 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/usb/core/devio.c b/drivers/usb/core/devio.c
index 545da37..04f7504 100644
--- a/drivers/usb/core/devio.c
+++ b/drivers/usb/core/devio.c
@@ -923,8 +923,8 @@ static int proc_do_submiturb(struct dev_
if ((ep->desc.bmAttributes & USB_ENDPOINT_XFERTYPE_MASK)
!= USB_ENDPOINT_XFER_CONTROL)
return -EINVAL;
- /* min 8 byte setup packet, max arbitrary */
- if (uurb->buffer_length < 8 || uurb->buffer_length > PAGE_SIZE)
+ /* min 8 byte setup packet, max 8 byte setup plus an arbitrary
data stage */
+ if (uurb->buffer_length < 8 || uurb->buffer_length > (8 +
MAX_USBFS_BUFFER_SIZE))
return -EINVAL;
if (!(dr = kmalloc(sizeof(struct usb_ctrlrequest), GFP_KERNEL)))
return -ENOMEM;
--
1.4.0
All the advantages of Linux Managed Hosting--Without the Cost and Risk!
Fully trained technicians. The highest number of Red Hat certifications in
the hosting industry. Fanatical Support. Click to learn more
http://sel.as-us.falkag.net/sel?cmd=lnk&kid=107521&bid=248729&dat=121642
_______________________________________________
linux-usb-devel@lists.sourceforge.net
To unsubscribe, use the last form field at:
https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
