On Fri, Oct 30, 2015 at 10:28:09AM +0100, Krzysztof Opasiak wrote: > > > On 10/30/2015 08:31 AM, Peter Chen wrote: > >Hi Krzysztof and Felipe, > > > >With commit (91c42b0d usb: gadget: loopback: Fix looping back logic > >implementation), the gadget loopback supports real loopback function > >that is read data from the host, and them send the same data back. > > > >But it breaks the testing function between f_loopback and usbtest, > >usbtest does not expect the data will be back from opposite endpoint, > >and our documentation (Documentation/usb/gadget-testing.txt) also > >says we can use usbtest to test f_loopback. > > > >How about supports old function as well as loopback function at the > >same time? > > Personally I don't agree with this approach. Loopback function had > been working until commit: > > e0857ce usb: gadget: loopback: don't queue requests to bogus endpoints > dated: Mon Oct 13 15:30:52 2014 -0500 > > After that it began to behave like /dev/null and /dev/zero so it was > more like SourceSink. Then commit: > > ec91aff7 Documentation: usb: LOOPBACK function testing > dated: Tue Dec 16 14:56:31 2014 +0100 > > added entry in documentation about testing the Loopback function but > in that time this function was not working correctly. Then with my > commit: > > 91c42b0 usb: gadget: loopback: Fix looping back logic implementation > dated: Wed Oct 14 22:49:40 2015 +0200 > > I have fixed loopback function so now it working now as it was > working before e0857ce. This time line shows that the documentation > has been added when function was not really working. So in my humble > opinion the broken part is the documentation and that's the place > for fix (and update testusb.c if you would like to use it for > testing loopback function). > > >I don't want to break the some usb tests I added which > >can test the maximum USB throughput for bulk. > > > > Is there any reason why didn;t you use SourceSink function which can > work exactly like loopback did before the fix (/dev/zero /dev/null)? > The SourceSink has only one request in queue, the performance is poor -- Best Regards, Peter Chen -- 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
