On Wed, Jun 12, 2019 at 01:46:06PM +0200, Oliver Neukum wrote: > > Thay is someething the virt_boundary prevents. But could still give > > you something like: > > > > 1536 4096 4096 1024 > > > > or > > 1536 16384 8192 4096 16384 512 > > That would kill the driver, if maxpacket were 1024. > > USB has really two kinds of requirements > > 1. What comes from the protocol > 2. What comes from the HCD > > The protocol wants just multiples of maxpacket. XHCI can satisfy > that in arbitrary scatter/gather. Other HCs cannot. We have no real way to enforce that for the other HCs unfortunately. I can't really think of any better way to handle their limitations except for setting max_segments to 1 or bounce buffering.
