> From: Felipe Balbi [mailto:balbi@xxxxxx] > Sent: Friday, September 30, 2011 12:26 PM > > Hi, > > On Fri, Sep 30, 2011 at 10:24:20PM +0300, Felipe Balbi wrote: > > This is actually a good point. We can't simply roundup request length on > > UDC driver because we don't know if gadget driver has allocated enough > > space should host send more data. > > > > OTOH, if we don't roundup request->lenght, driver won't work *always* on > > SuperSpeed. > > > > From DWC3 point this patch should be acceptable, but there could be > > another controller with a different quirk where DMA wouldn't complete > > unless we pass correct size, dunno. > > > > Alan ? > > I just remembered, though, that MSC has no short packets, that's why we > set short_not_ok flag. So, is this really necessary ? I'll run some > extra tests on monday. Hi Felipe, Yes, MSC does have short transfers at Super Speed. Remember that the typical backing store is a Fat FS, with 512-byte sectors. Things are not always going to be aligned to the 1K max packet size of Super Speed bulk endpoints. So the host is going to make requests that are not 1K aligned, and we must handle that. I saw this myself in our lab when testing the latest DWC3 driver with the Super Speed mass-storage gadget, hence the patch. -- Paul ��.n��������+%������w��{.n�����{���)�� jg��� �����ݢj����G���� ���j:+v���w�m������w�������h�����٥
