On Wed, 2012-08-22 at 16:33 -0500, Larry Finger wrote:

On 08/22/2012 12:15 AM, Eric Dumazet wrote:

quoted

This particular commit is the start of a patches batch that ended in the
generic TCP coalescing mechanism.

It is known to have problem on drivers doing skb_clone() in their rx
path.

Current kernels should be ok, because coalescing doesnt happen if the
destination skb is cloned (skb_cloned(to) in skb_try_coalesce())

The skb_clone() call is not the source of the problem for r8712u, as it is only 
used when a memory allocation fails, which is not happening. The suggestion did 
lead to another patch that I had been preparing. The initial allocation of RX 
buffers used a size of 30720 bytes, while 9100 is sufficient to allow 
aggregation. Upon reducing the buffer size, the driver now works for me. I am 
now awaiting tests by the OP on the Red Hat bugzilla before sending the patch 
upstream.

So far, no ideas for the problem in connecting to WPA1 networks.

Changing the allocation size removes the problem ? thats really strange.

If you try different sizes in the 9100-30720 range, can you pinpoint the
failure threshold ?