On Tue, Jan 03, 2017 at 04:34:48PM +0100, Greg KH wrote:
> On Tue, Jan 03, 2017 at 09:15:06AM -0600, Bin Liu wrote:
> > During dma teardown for dequque urb, musb might generate bogus rx ep
> > interrupt even when the rx fifo is flushed. As mentioned in the current
> > inline comment, clearing ep interrupt in the teardown path avoids the
> > bogus interrupt.
> > 
> > Before this change, any of the follow log messages could happen when
> > musb load is high.
> 
> What "change" caused this?
> 
> > 
> >     musb_host_rx 1853: BOGUS RX2 ready, csr 0000, count 0
> > 
> >     musb_host_rx 1936: RX3 dma busy, csr 2020
> > 
> > cc: sta...@vger.kernel.org # 4.1+
> 
> Do you have a git commit id that caused this issue?

This patch was posted in [1].

I believe this issue exists from day one of the musb driver, not caused
by any recent change. I saw those kernel logs before in a few cases, but
it was really hard to reproduce, only until recently with a use case
with FT4232H, which can trigger the issue constantly within a few
minutes.

Since I only tested the patch back to v4.1, so I only cc'd stable for
4.1+.

[1] http://marc.info/?l=linux-usb&m=147996265122151&w=2

Regards,
-Bin.

> 
> thanks,
> 
> greg k-h
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