On Sun, Jun 23, 2013 at 04:56:22PM -0500, Daniel Santos wrote: > On 06/23/2013 01:43 PM, Greg KH wrote: > >On Sun, Jun 23, 2013 at 01:13:34PM -0500, Daniel Santos wrote: > >>So I'm working on this MCP2210 driver which talks in 64-byte > >>request/response pairs using interrupt URBs (it can be used with > >>hid-generic, but I don't want to do that). I'm testing on a > >>Raspberry Pi Model B using the Raspbian 3.9.7 kernel. > >My deepest sympathies, the USB host controller driver on the Raspberry > >Pi is a huge shop of horrors, it's amazing that it works at all, and > >when it does, it eats huge amounts of CPU for no known good reason. > > > >Good luck with it, and be happy that it's working for you in the first > >place :) > > > >Anyway... > > Well, our project needs more than two USB ports, and we were looking > at the model A anyway, so maybe I should just find some nice USB hub > chip and/or PIC that uses SPI and has a good stable driver and hook > it up via the Pi's SPI interface? I know that sounds kinda stupid > when it already has the USB interface on it, but if it's an unstable > thing, it may be good since we're going to be moving big telescopes > around with these things and it would be bad if it suddenly whacked > somebody in the head because of a bad USB message. :)
I would trust SPI over USB, especially as you have more "direct" control over SPI than USB. But if you only have USB, then perhaps you should use a different device than the RPI? Like a BeagleBoneBlack? Or some other tiny Linux machine, there are a lot of them under 100 USD these days. Best of luck, greg k-h -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
