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

[Tony Lindgren <tony@atomide.com>]

* Yegor Yefremov <yegorslists@googlemail.com> [191021 01:40]:
> Hi Tony,
> 
> On Thu, Oct 3, 2019 at 10:39 AM Yegor Yefremov
> <yegorslists@googlemail.com> wrote:
> >
> > Hi Tony,
> >
> > On Wed, Oct 2, 2019 at 6:52 PM Tony Lindgren <tony@atomide.com> wrote:
> > >
> > > * Yegor Yefremov <yegorslists@googlemail.com> [191002 06:57]:
> > > > On Wed, Oct 2, 2019 at 12:03 AM Tony Lindgren <tony@atomide.com> wrote:
> > > > > The other way to fix this would be to just wake up cpp41 in
> > > > > cppi41_dma_prep_slave_sg() and return NULL so that we can
> > > > > have musb_ep_program() continue with PIO while cppi41 is
> > > > > asleep.
> > > > >
> > > > > Anyways, care to try it out and see if it fixes your issue?
> > > >
> > > > The fix is working but on the first invocation, I get this output
> > > > (minicom provokes the same output):
> > >
> > > > # serialtest.py -c 2 /dev/ttyUSB0 /dev/ttyUSB0
> > > ...
> > > > [  210.940612] [<c065fc94>] (__rpm_callback) from [<c065fd60>]
> > > > (rpm_callback+0x20/0x80)
> > > > [  210.948402] [<c065fd60>] (rpm_callback) from [<c065f7cc>]
> > > > (rpm_resume+0x468/0x7a0)
> > > > [  210.956018] [<c065f7cc>] (rpm_resume) from [<c065fb50>]
> > > > (__pm_runtime_resume+0x4c/0x64)
> > > > [  210.964086] [<c065fb50>] (__pm_runtime_resume) from [<bf020940>]
> > > > (cppi41_dma_prep_slave_sg+0x20/0xfc [cppi41])
> > >
> > > OK so that won't work, thanks for testing. Here's the alternative
> > > patch to try along the lines described above that just wakes up
> > > cppi41 and returns NULL so musb_ep_program() can continue with PIO
> > > until cppi41 is awake.
> >
> > I'm out of the office for some weeks and don't have access to my hw.
> > I'll make the test as soon as I'm back.
> 
> I've tested your patch with both systems (with and without a hub) and
> everything is working as expected.

OK good to hear, I just sent it out with a proper description as:

[PATCH] dmaengine: cppi41: Fix issue with musb and ftdi uart

Regards,

Tony