Re: [Question] Always got STALL in MUSB Host driver

[David Brownell <david-b@pacbell.net>]

On Sunday 18 November 2007, Nazim Khan wrote:
> Currently I am trying to get the DMA Mode (cppi dma) working in High Speed.

CPPI being what I class as a hardward design goof,
especially for packet RX.  Certain traffic patterns
seem almost OK, others don't.


> The driver works for sometime and then the Tx channel get snapped.

DMA-only ... or also with PIO?


> I am working on 2.6.18 Davinci kernel and tried to see the updates on
> musb driver in 2.6.23 driver of both (omap and davinci). On davinci I
> don't see much changes except the musb
> driver falling in kernel coding convention.

There are many more changes than that ... though certainly
there's a high volume of cleanup changes, and you may easily
have missed the other changes in the middle of those.

A more current kernel would be to your advantage...

 
> Unfortunately I also don't USB analyzer to really heck out what
> exactly happening there.

If your budget allows, www.totalphase.com has a rather
inexpensive one ($US 1200, what just a few wasted days
could cost) that handles high speed.


> ----------------- Error Log ------------------------
> <4>eth1: Tx timed out.
> <4>We are going to usb_kill_urb @ kevent
> <0>Calling cppi_channel_abort
> <7>musb_cleanup_urb 2374: abort TX1 DMA for urb c2dbb380 --> 0
> <7>__musb_giveback 310: complete c2dbb380 (-2), dev2 ep1out, 1543/1543
> <3>Tx status: -2error in tx submit urb: -1Clear Tx Busy
> <4>error in tx submit urb: -1Clear Tx Busy
> <6>NETDEV WATCHDOG: eth1: transmit timed out
> ____________________________________

It's not clear what that' supposed to indicate.  It looks
like some TX DMA completion logic didn't trigger, which
caused the TX timeout and urb cancelation ... which then
reported that everything had been transmitted.

- Dave


> 
> regards,
> Nazim
> 
> On Nov 19, 2007 12:04 PM, David Brownell <david-b@pacbell.net> wrote:
> > On Sunday 18 November 2007, Nazim Khan wrote:
> > > Hi Dave,
> > >
> > > Was that in DMA mode or PIO Mode?
> >
> > Probably PIO, since that's usually the first stage of
> > debugging given a choice of modes.
> >
> > I vaguely recall it was one of those two modes, but
> > don't recall which one.  If it was DMA, I sure don't
> > recall which of the several DMA engine wass involved.  ;)
> >
> > - Dave
> >
> >
> >
> > > regards,
> > > Nazim
> > >
> > > On Nov 16, 2007 12:13 AM, David Brownell <david-b@pacbell.net> wrote:
> > > > On Thursday 15 November 2007, Tony Lindgren wrote:
> > > > > Hmm, I never got double buffering to reliably work on tusb as far as I
> > > > > remember. I guess Dave got it working on DaVinci, so maybe he has some
> > > > > pointers.
> > > >
> > > > It's been some time since I tried that.  What I vaguely recall
> > > > is that it worked on the peripheral side, but on the host side
> > > > there was a issue if for example both sides (tx, rx) of a given
> > > > FIFO tried to do things at the same time.
> > > >
> > > > The driver code has improved a lot since I saw those failures,
> > > > so I wouldn't trust those memories to indicate anything specific
> > > > about current behavior.
> > > >
> > > > - Dave
> > > >
> > >
> >
>