Hi, John Youn <John.Youn@xxxxxxxxxxxx> writes: > On 8/26/2016 12:48 AM, Felipe Balbi wrote: >> >> Hi, >> >> John Youn <John.Youn@xxxxxxxxxxxx> writes: >>> I was wondering if anyone is using the f_tcm function? Specifically >>> for UAS in superspeed with streams? Any idea if it is being using in >>> production for this anywhere? >>> >>> I've been trying to get the tcm gadget running without success. It >>> seems I need to configure the target system via configfs and somehow >>> interface it to this gadget. But I have not found any documentation or >>> examples on how to get it working. Anyone have ideas or pointers? >> >> Sebastian has posted his scripts here several times, it's in the >> archives :-) > > I found some scripts before but none of them resulted in a working > system. Though I did manage to get something semi-working > eventually. It would still be nice to have some documentation about > this part especially as I have no knowledge of the target side and no > idea what those scripts are doing. What do you mean by "semi-working"? How far did you get? Can you capture tracepoints so we figure out what's wrong? # mkdir -p /t # mount -t tracefs none /t # echo 8192 > /t/buffer_size_kb # echo 1 > /t/events/dwc3/enable (trigger issue) # cp /t/trace ~/trace.txt Send me trace.txt ;-) >> There's also a TCM python tool somewhere which helps with this. I >> haven't used f_tcm in a long while, but Sebastian and I used it long >> back to test streams with dwc3. > > Have you tried it recently? Or do you know of anyone who has? Sebastian is the only one I know who has used this in the past. >>> Just from the code it seems there will be some fundamental issues with >>> it, such as the value of maxpacket size and some alt-interface >>> stuff. At least when used with DWC3. >> >> such as? > > I'll see if I can write up the exact issues later. I have to go back > to my notes to remind myself. > > But just in trying to get it to work, these issues make me suspect no > one is using this driver in superspeed, or at least regularly testing > it, let alone using it in production. that's probably true, but it's not enough argument to have a duplicate implementation of it :-) Rather, we should be figuring out what's broken and fixing it. I have a ton of other stuff to be done, but I'll add this to my queue, no issues. -- balbi
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