On 09/10/14 08:31, Gerd Hoffmann wrote: > Hi, > >> So at this point I'm wondering why guests and "info qtree" are contradictory, >> and whether the combination of OVMF and OS X tickle some qemu usb emulation >> bug differently than all other (working) combinations ? > > It's due to the way how usb1 compatibility was implemented when ehci was > introduced ... > > Each usb 2.0 port is linked to both uhci and ehci controller. ehci > controls the port routing (i.e. whenever a device shows up @ uhci or > ehci). There is one global bit and one per-port bit which control the > routing.
Is "4.2.1 Port Routing Control via EHCI Configured (CF) Bit" related? The Configured Flag (CF) is the global one apparently, and the Port Owner bit is per port. In "MdeModulePkg/Bus/Pci/EhciDxe/", the CF flag seems to be called CONFIGFLAG_ROUTE_EHC, and Port Owner is PORTSC_OWNER. > The global bit says whenever the ports should be routed to ehci by > default or not. EHCI driver software is supposed to flip that bit at > initialization time to get all devices routed to ehci. Power-on default > is route everything to uhci, so if the OS knows nothing about ehci all > usb devices will show up on the uhci companion. > > The per-port bit should be flipped by the ehci driver for usb1 devices, > so they are handed over to uhci as ehci supports usb2 devices only. > > > In qemu this is implemented by having ehci managing the usb bus and uhci > registering its ports as companion ports. ehci emulation will either > handle the devices itself or call uhci, depending on how the guest has > configured the routing. > > There is even a basic test case for that: tests/usb-hcd-ehci-test.c > > Because ehci manages the bus the usb devices show up on ehci in 'info > qtree', no matter how the port routing is configured. > >> Not sure how I'd force the keyboard and mouse onto the default uhci1 and/or >> uhci2 (from the qtree perspective), since they're given empty IDs by default >> (and my qemu command line kung-fu is weak in this area). > > Pure uhci working fine hints it most likely is a bug somewhere in the > port routing code. Could be in ovmf, but could be qemu too. You can't > force it from outsize, port routing is guest business. > > What happens if you build ovmf with uhci but without ehci driver? Does > that work? I'm glad I happened to suggest the same. ;) Laszlo
