On Wed, 25 Mar 2015, Peter Chen wrote: > > > How do you know the frame has filled already at that time? The software > > > makes sure it fills frame in time before next time frame? > > > > I'm not sure I understand the question. > > > > The USB analyzer log showed something like this (this is a rough > > approximation because I didn't keep the original analyzer output file): > > > > Timestamp Transaction > > s.mmm uuu > > ----------------------------------- > > 0.000 000 SOF > > 0.000 030 Isoc OUT > > 0.000 091 Isoc OUT > > 0.000 162 Isoc OUT > > 0.000 224 Isoc OUT > > 0.001 000 SOF > > > > In this example, there are 4 OUT transfers taking about 290 us and then > > nothing else for the rest of the frame. > > > > I also know, from looking at the "periodic" file in the EHCI debugfs > > directory, that each frame was linked to 8 siTDs: > > > > siTD OUT, Smask = 0x01, Cmask = 0x00, transfer length = 64 > > siTD OUT, Smask = 0x01, Cmask = 0x00, transfer length = 64 > > siTD OUT, Smask = 0x02, Cmask = 0x00, transfer length = 64 > > siTD OUT, Smask = 0x02, Cmask = 0x00, transfer length = 64 > > siTD IN, Smask = 0x04, Cmask = 0x70, transfer length = 64 > > siTD IN, Smask = 0x04, Cmask = 0x70, transfer length = 64 > > siTD IN, Smask = 0x08, Cmask = 0xe0, transfer length = 64 > > siTD IN, Smask = 0x08, Cmask = 0xe0, transfer length = 64 > > > > I did not debug too many for Host ISOC, I just want to make sure the > siTD is ready before the controller read it? Yes, all the siTDs were ready before the controller read them. I know because it worked perfectly when I used a high-speed hub instead of a full-speed hub. > Does it fail at the beginning or running several cycles? The isochronous streams did not all start at the same time. First one isoc-OUT stream started, then the second stream, then the third stream, then the fourth stream. After that, the isoc-IN streams started, one by one. The controller worked okay up until the time the isoc-IN streams began. Before that, it transmitted the OUT packets correctly. After the isoc-IN streams started, the controller sometimes transmitted only the four OUT packets (like in the example above), sometimes a mixture of OUT and IN packets, and sometimes only one or two IN packets. The behavior was very erratic. Alan Stern -- 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
