FT4232H on ehci problem (was Re: usb/143832: [uftdi] Request support for FTDI FT4232H.)

[Hans Petter Selasky]

On Monday 15 February 2010 14:37:10 UEMURA Tetsuya wrote:
> > Now I have a problem with the device. When it is attached on ehci, it
> > always stalls when I do a bit heavy communication over it. This doesn't
> > happen with uhci (kldunload ehci or whatever).
> 
> I did further investigation myself and found that wMaxPacketSize is
> 0x0200 when the device was on ehci (0x0040 on uhci), and the device
> seemed to work (at least not stall) on ehci if I changed
> UFTDI_[IO]BUFSIZE to 512.
> 
> The device however stopped working on uhci with such a modification.
> 
> By the way, the official FTDI Linux driver found at
> http://www.ftdichip.com/Drivers/VCP/Linux/ftdi_sio.tar.gz
> also seemed to specify 512 as its buffer sizes.
> 
> Can anyone help me?
> 
> Regards.
> 

What platform are you running?

--HPS