Re: musb: cppi41: broken high speed FTDI functionality when connected to musb directly

[Tony Lindgren <tony@atomide.com>]

* Yegor Yefremov <yegorslists@googlemail.com> [191001 09:20]:
> On Tue, Oct 1, 2019 at 10:03 AM Johan Hovold <johan@kernel.org> wrote:
> >
> > On Mon, Sep 30, 2019 at 09:54:11PM +0200, Sebastian Reichel wrote:
> > > Hi,
> > >
> > > On Mon, Sep 30, 2019 at 08:23:30AM -0700, Tony Lindgren wrote:
> >
> > > > Actually playing with the cppi41 timeout might be more suitable here,
> > > > they use the same module clock from what I remember though. So
> > > > maybe increase the cppi41 autosuspend_timeout from 100 ms to 500 ms
> > > > or higher:
> > > >
> > > > # echo 500 > /sys/bus/platform/drivers/cppi41-dma-engine/47400000.dma-controller/power/autosuspend_delay_ms
> > > >
> > > > If changing the autosuspend_timeout_ms value does not help, then
> > > > try setting control to on there.
> > >
> > > I did not check the details, but from the cover-letter this might be
> > > woth looking into:
> > >
> > > https://lore.kernel.org/lkml/20190930161205.18803-1-johan@kernel.org/
> >
> > No, that one should be unrelated as it would only prevent later suspends after
> > a driver has been unbound (and rebound).
> 
> I've tried to increase the autosuspend_delay_ms and to set control to
> "on" but nothing changes. Below you can see the output of my testing
> script [1] (Py2 only). As one can see, the first cycle i.e. after the
> port is open for the first time, fails. But the subsequent cycle is
> successful. If you invoke the script again, everything repeats.
> 
> I've also made printk() in cppi41_run_queue() and it looks like this
> routine will be called from cppi41_dma_issue_pending() only in the
> beginning of the second test cycle.

So sounds like for you intially cppi41_dma_issue_pending() has
!cdd->is_suspended and just adds the request to the queue. And
then cppi41_run_queue() never gets called if this happens while
we have cppi41_runtime_resume() is still running?

Can you check that cppi41_dma_issue_pending() really gets
called for the first request and it adds the request to the
queue by adding a printk to cppi41_dma_issue_pending()?

> [1] http://ftp.visionsystems.de/temp/serialtest.py

For me this script somehow fails to configure the ports with:

$ python2 serialtest.py -c2 /dev/ttyUSB0 /dev/ttyUSB0
Openning one of the serial ports failed
Openning one of the serial ports failed

The permissions are set properly as I have minicom working..
So still no luck reproducing.

Regards,

Tony