* Felipe Balbi | 2011-08-29 15:55:09 [+0300]: >On Mon, Aug 29, 2011 at 02:49:03PM +0200, Sebastian Andrzej Siewior wrote: >> >On Mon, Aug 29, 2011 at 01:48:14PM +0200, Sebastian Andrzej Siewior wrote: >> >> >A better approach might be to introduce a "quirks" field on struct >> >> >usb_gadget, as have gadget drivers check for that. Something like: >> >> > >> >> > if (gadget->quirks & GADGET_NEEDS_ALIGNED_OUT) >> >> > req->length = gadget->ep0->maxpacket; >> >> > else >> >> > req->length = len; >> >> >> >> This is bad because you have to ensure the buffer is large enough. For >> >> ep0 the composite framework allocated bMaxPacketSize0 anyway right? >> > >> >composite has a 1k buffer. The buffer has to be big enough for a big >> >load of descriptors. >> >> If so, why not unconditionally queue maxpacket size then? The host does >> not see a difference. > >What if we have controllers which need request to be passed with correct >size ? I mean, what if there's some DMA engine where if you don't start >a transfer with correct size, it will never finish ? It is a short transfer in OUT direction. Don't these have to finish anyway? >Until we know this won't cause problems for anyone else, I rather keep >this workaround on dwc3 driver, since this is purely a dwc3 limitation. Yes, I'm okay with this workaround beeing dwc3 specific. In the long term I would prefer not having udc have to work around gadget's bugs. Sebastian -- 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
