Re: USB faulty on ts7800s
- Sounds like the USB driver doesn't support a particular transfer type or feature.
Have you checked this.
--- In email@example.com, Andrew Taylor <andrewt@...> wrote:
> This is to vent my frustration with USB on ts7800. I'm trying
> to deploy systems with Maxon BP3 3g usb wireless modems (sierra
> wireless chipset). These work on ts7200 & x86 fine. But don't work
> connected to a ts7800 with 2.6.21-ts(oct102008) +airprime or with
> 2.6.30-rc7(http://ts78xx.digriz.org.uk/)+option. The option module failes
> immediately giving messages like this: "option: option_instat_callback:
> error -71" which apparently indicates a low-level USB problem. I've tried
> multiple ts7800 boards and multiple USB modems.
> Fortunately if a (non-powered) USB hub is interposed the modem seems to
> work reliably. But the extra power consumption of the hub is annoying
> because my systems are solar-powered.
> More frustrating is audio. I capture sound using custom-built usb sound
> boards based on AVRs and previously using Griffin iMics. Again these work
> with ts7200 (same EABI kernel & userland) & x86 but fail with ts7800s
> running both 2.6.21-ts and 2.6.30-rc7. As far I can tell the problem
> is not ALSA, it seems to be a low level hardware/software bug in the
> ts7800's USB. If a (non-powered) USB hub is interposed, sound capture
> sometimes works but it depends on the hub, the sampling rate and other
> configuration details. I can't make it reliable enough for my purposes.
> I don't need sound playback - but it also seem to have problems.
> I haven't seen any problems with USB storage devices on the ts7800 but I
> don't use them much. The above problems occur if you power the devices
> separately or via the ts7800.
> So the moral is, don't count on non-storage USB devices working on
> a ts7800. In particular USB audio is likely to fail. And interposing
> a hub might help. As consequence I'm looking for alternative low power
> boards with SATA+USB 2.0. This one looks interesting:
> More suggestions welcome.
- The Marvell SoC doesn't support isochronous transfers usually needed for USB sound cards. USB 2.0 doesn't have isochronous transfer at all and thus some devices work and some don't. Being an unreliable data transfer method, it is used only for devices that can cope with missing chunks of data, thus USB storage devices never use it.
I have seen myself in the same situation with some exotic devices and had to find different solutions. Unfortunately, in my case an USB hub never helped.
So, as long as you know what to use the board for, it will do the job properly. But read the SoC errata PDF before!
- On Wed, Jul 01, 2009 at 09:02:23AM +0300, Catalin Ionescu wrote:
> The Marvell SoC doesn't support isochronous transfers usually neededThanks. The 50 page errata includes this cryptic statement: "For USB
> for USB sound cards. USB 2.0 doesn't have isochronous transfer at all
> and thus some devices work and some don't. Being an unreliable data
> transfer method, it is used only for devices that can cope with missing
> chunks of data, thus USB storage devices never use it.
> I have seen myself in the same situation with some exotic devices and
> had to find different solutions. Unfortunately, in my case an USB hub
> never helped.
> So, as long as you know what to use the board for, it will do the job
> properly. But read the SoC errata PDF before!
Isochronous mode support contact a local Marvell Field applications
Engineer or reprentative. Workaround: none" - hence presumably my USB
audio problems. One of the other USB errata presumably explains my 3G
I guess the moral is don't count on USB devices working with a ts7800 until
you've tested them - and I need to find an alternative board.