USB audio device on Raspberry Pi - link_elf: symbol isa_dmastatus undefined

[Bernd Walter]

On Mon, May 05, 2014 at 01:24:24PM -0600, Ian Lepore wrote:
> On Mon, 2014-05-05 at 20:27 +0200, Bernd Walter wrote:
> > On Mon, May 05, 2014 at 10:37:09AM -0700, John-Mark Gurney wrote:
> > > Hans Petter Selasky wrote this message on Thu, May 01, 2014 at 17:08 +0200:
> > > > On 05/01/14 01:34, Johny Mattsson wrote:
> > > > >On 1 May 2014 00:14, Ian Lepore <ian at freebsd.org> wrote:
> > > > >
> > > > >>I was doing some testing on a wandboard (about twice as fast an an rpi)
> > > > >>with
> > > > >>more than 20k int/sec without having any problems.
> > > > >>
> > > > >
> > > > >On a similar note, I've pushed an i.MX 283 (400MHz) board to above 300k
> > > > >int/sec, on Linux. Admittedly at that point my shell wasn't what you'd call
> > > > >"responsive" however =) The ISR in that scenario was the GPIO handler, so
> > > > >probably a bit more light-weight than an audio ISR.
> > > > 
> > > > Hi,
> > > > 
> > > > I'll have a look and see if I can fix it.
> > > 
> > > So, I have both a BBW and a BBB and both devices don't have working
> > > USB...  If I plug in a device, like a uftdi serial adapter, the blue
> > > light flashes briefly but then stays off... It should stay on...
> > 
> > AFAIK we don't switch any LED at all, so this probably is a power problem.
> > What rating has your power supply?
> > Do you use the barrel or USB plug to power the board?
> > I think you need to use the barrel plug for additional load, since
> > the board has some kind of current limitation for the USB connector.
> > 
> 
> That LED behavior is the FDTI adapter hardware.  Depending on how you
> wire them, you can get several behaviors out of FTDI LEDs.  If you wired
> an LED to the PWREN# it would behave like that if the host system told
> the hub to shutdown port power.  I had such a problem with the new FTDI
> H-series chips once, because their device descriptor says they need up
> to 150mA (although in normal uart modes they never draw anywhere near
> that).  I was plugging them into a bus-powered hub and it would power
> up, read the descriptor, and power right back down.  When I plugged the
> hub's power adapter in it started working fine.

Oh - I wasn't thinking about blue LED to be something on the FTDI device,
because I thought it to be gerneric uftdi.

About the PWREN behavour you describe, there is something wrong as well.
If your device claims 150mA - at least according to descriptor - and the
OS says no to 150mA. then why is the PWREN enabled at all?
It should stay down, because PWREN primary use is not to drive a LED, but
to drive power to auxillary logic after the host give his OK.
For example in one of my devices with 12V signals I use PWREN to activate
the 5V to ±12V DC-DC converter.

-- 
B.Walter <bernd at bwct.de> http://www.bwct.de
Modbus/TCP Ethernet I/O Baugruppen, ARM basierte FreeBSD Rechner uvm.