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[Discuss-gnuradio] USB2 high speed vs. full speed.
From: |
Berndt Josef Wulf |
Subject: |
[Discuss-gnuradio] USB2 high speed vs. full speed. |
Date: |
Sun, 13 Feb 2005 23:41:24 +1030 |
User-agent: |
KMail/1.7.2 |
G'day,
The following are the reported devices and their configuration after loading
the firmware and fpga:
Reported devices by kernel during at bootup
hci0 at pci0 dev 29 function 7: Intel 82801DB USB EHCI Controller (rev. 0x01)
ehci0: interrupting at irq 11
ehci0: EHCI version 1.0
ehci0: companion controllers, 2 ports each: uhci0 uhci1 uhci2
usb3 at ehci0: USB revision 2.0
uhub3 at usb3
uhub3: Intel EHCI root hub, class 9/0, rev 2.00/1.00, addr 1
uhub3: single transaction translator
uhub3: 6 ports with 6 removable, self powered
NB: According to a GnuRadio Wiki article, the Intel 82801DB device is
acclaimed to be the best performer!
Reported configuration interrogated from userland
usbdevs -v
[,,,]
Controller /dev/usb3:
addr 1: high speed, self powered, config 1, EHCI root hub(0x0000),
Intel(0x8086), rev 1.00
port 1 addr 2: high speed, self powered, config 1, USRP Rev 2(0x0002), Free
Software Folks(0xfffe), rev 1.02
port 2 powered
port 3 powered
port 4 powered
port 5 powered
port 6 powered
I was led to believe that the FX2 interface is suppose to be configured as a
fullspeed device. This doesn't appear to be the case as it is reports the
configuration of a high speed device.
A evaluation of the USRP USB interface only managed to push 4MB/sec data
bandwith which is below the expectation of a full speed USB device.
test_usrp_standard_{tx,rx} utilities report underruns and overruns
respectively until the decimation/interp value is adjusted to a value
accommodating this speed.
Not being an expert in USB software development this leads me to my question:
What is required to get the show running at the next level of speed? In which
aspects does the fusb_linux implementation differ from that of the generic
version considering that both make use of the libusb library.
Currently, most example applications run with only a few overrun/underrun
messages chiefly caused due to activities of other applications running on
the same system, such as KMail checking for new mail etc., at the current
4MB/sec limitation. "top" reports a CPU load of less than 10% for most
GnuRadio example programs run on this system.
Any help, pointers and tips are very much welcomed and appreciated.
73, Berndt
VK5ABN
--
Every man who says frankly and fully what he thinks is doing a public service.
[Leslie Stephen]
- [Discuss-gnuradio] What is a ppio_ppdev?, Berndt Josef Wulf, 2005/02/12
- Re: [Discuss-gnuradio] What is a ppio_ppdev?, Eric Blossom, 2005/02/12
- [Discuss-gnuradio] usrp oscope, fft_simple & fft, cfk, 2005/02/12
- Message not available
- [Discuss-gnuradio] usrp_siggen.py & usrp_fft.py, cfk, 2005/02/12
- [Discuss-gnuradio] USB2 high speed vs. full speed.,
Berndt Josef Wulf <=
- Re: [Discuss-gnuradio] USB2 high speed vs. full speed., Eric Blossom, 2005/02/13
- [Discuss-gnuradio] aUaU, cfk, 2005/02/13
- Re: [Discuss-gnuradio] aUaU, Eric Blossom, 2005/02/13
- Re: [Discuss-gnuradio] aUaU, cfk, 2005/02/13
- Re: [Discuss-gnuradio] aUaU, Eric Blossom, 2005/02/14
Re: [Discuss-gnuradio] What is a ppio_ppdev?, Stephane Fillod, 2005/02/19