Re: OMAP L138 with exar usb serial converter

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Em 22-06-2012 14:39, Greg KH escreveu:
On Fri, Jun 22, 2012 at 12:07:57PM +0100, Aníbal Almeida Pinto wrote:
Em Qui 21 Jun 2012 19:19:40 WEST, Aníbal Almeida Pinto escreveu:
Em 21-06-2012 18:12, Greg KH escreveu:
On Thu, Jun 21, 2012 at 10:34:15AM +0100, Aníbal Almeida Pinto wrote:
Hi,

we are using an board with a OMAP L138 with a exar xr21v141x [1], an
usb to two serial port converter. The exar have drivers [2] for
linux but aren't on mainline.

We are having problems when using both ports at same time, the
driver only receive the information from one port after the other
was closed.

On musb_core.c there are some information about problems with
multipoint devices. The behaviour that we are seeing is due to this
?

Any way of resolve this, being able to receive data from both ports
when both are open ?

We are having problems compiling the latest release of linux-davinci
kernel with usb support, even usb 1.0 interface don't work. Any info
about this ?

As you are stuck using their out-of-tree driver, I suggest you ask them
about this, as there's nothing we can really do here to help you out :(

I will ask to them but one issue is that the driver works on i386.

The musb_core.c have some comments about possible problems and I am
thinking if this device can demonstrate one of it :-/

Is a way of validating this ?

Now we could take their driver and add it to the kernel tree, but that's
a more long-term solution, not something to help you out right now,
sorry.

If license allow it, anyone can pick on the driver and try to submit ?
Don't need someone from the company or someone that maintain the driver ?

Thanks for your time.

I can reproduce this behavior with a different approach.

I connected a hub to OMAP L138 with two usb to serial converter from
Prolific Technology Inc that uses the pl2303 driver.

When opening one of the devices I can communicate and everything work fine.

When trying to open a second one, with the first connected, I
receive this error:

	pl2303 ttyUSB1: pl2303_open - failed submitting interrupt urb, error -28

This setup works on i386, so can this be a problem from MUSB ?

That error is saying that the usb bus has no more bandwidth in order to
be able to accept this transfer.  Which seems odd, you should ask the
musb authors about this.

Added maintainer of MUSB to the fight :)

This happen when have a hub with two pl2303 usb serial converter, the first work when opening second report error:
	failed submitting interrupt urb, error -28

Any idea why this happen ?

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