On Friday, February 20, 2015 at 04:22:58 AM, Stephen Warren wrote: Hi!
[...] > >> Existing code that invokes USB transfers will call (a) once. (a) will > >> call (b) as many times as needed to break up the packet into small > >> chunks. (b) will either send the transaction to the HW (HS devices or > >> directly attached LS/FS devices), or perform the split transaction > >> handling (remotely attached LS/FS devices). > >> > >> Does that sound like a reasonable approach? > >> > >> I can start looking into getting split transactions going; I just > >> couldn't motivate myself last Friday night. > > > > Do you plan to do this on the USB stack level or USB controller driver > > level please ? > > I expect I'd put at least the split transaction stuff into the USB > controller driver. While I'm not that familiar with anything other than > standard EHCI, I'd guess the need to manually manage split transaction > was unique to DWC2? Looks that way. +CC Kishon , what about DWC3 ? > The split of transfers into max-packet-sized transfers could plausibly > be useful in the core, but again my guess is that the need to do this is > DWC2-specific? Kishon ? > >> 3) > >> > >> On the RPI 2, even directly attached HS devices (i.e. the on-board USB > >> hub, Ethernet) don't work correctly. I haven't tracked down the cause > >> yet, since I got side-tracked on the two issues above, initially > >> thinking they might have the same/similar root-cause. However, I don't > >> think this issue is related, since the RPi2 on-board devices don't fall > >> into either of the categories above. > > > > Do you get some kind of an error message ? > > Yes. It's similar to the message about "can't read descriptor" that I > used to get with a LS device on the original RPis, which is why I > started looking at keyboards. Your patch to split up large transactions > didn't affect this, so I believe they're separate issues now. OK [...] _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot