On Wed, 12 Dec 2007, Alessandro Paolinelli wrote: > Dear Mr Stern, > > I'm an italian engineer who are working on a usb device that use cdc_acm > usb driver. > > The device in question is not a modem. > We configure it as full-speed device(12 Mbps) with bulk transfer (bulk > packet size = 64) > > We have slower performance in USB transfer rate(450 Kbps under linux > instead of 7Mbps under windows) performing write operations. > > We have see ,with oscilloscope's aid,that the problem is relating to > bulk packet frequency in the URB frame : we have only one packet each > URB frame (multiple in windows). > > How can we increase this feature? > Should we choose another transfer/endpoint types?
No. > Should we modify our driver,cdc_acm module,uhci_hcd module or what > else ? Your driver? Aren't you using the cdc_acm driver? > All suggestions are very appreciated. I don't know much about how the cdc_acm driver works. However I suspect the problem is that your test program doesn't submit data quickly enough. Maybe someone more familiar with cdc_acm can give a better answer. Alan Stern - To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
