On Fri, May 6, 2016 at 8:00 AM, Dean Jenkins <Dean_Jenkins@xxxxxxxxxx> wrote: > My conclusion is that your USB to Ethernet Adaptor is not running at high > speed (480Mbps) mode which is causing a partial loss (corruption) of > Ethernet frames across the USB link. A USB Protocol Analyser or software > tool usbmon could be used to confirm this scenario. > > Therefore please retest with a working high-speed USB hub or remove the > full-speed USB hub from the test environment and directly connect the USB to > Ethernet Adaptor to the root hub of the USB port. Then repeat the tests to > see whether anything improved. > > In other words, you need to eliminate the dmesg messages saying "not running > at top speed; connect to a high speed hub". The aarch64 system has a quirk that at the moment limits it to the slower full-speed mode, which also exacerbates the issue (basically taking a fairly slow 1.1.Mb/s network connection without your patch, to an almost unusable 30Kb/s with it). But that isn't the case on the x86_64 system, which is seeing a very similar problem (though the performance effect isn't nearly as bad, as the error rate in time seems relatively similar on both, and I think my scp transmissions are cpu bound on this atom board :). thanks -john -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
