>> I think this debugfs code is just called too early. It shouldn't need to check new_ring >> pointer at all. >> >> I wrote a fix that changes the order and makes sure endpoint is enabled and ring >> pointer is set correctly before we call xhci_debugfs_create_endpoint() >> >> https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgit.kernel.o >> rg%2Fpub%2Fscm%2Flinux%2Fkernel%2Fgit%2Fmnyman%2Fxhci.git%2Fcommit%2F%3Fh%3Dfo >> r-usb-linus%26id%3Dcf99aef5624a592fd4f3374c7060bfa1a65f15df&data=02%7C01%7 >> Cjun.li%40nxp.com%7C73e4663a6f6641fbb8b308d84f3d021a%7C686ea1d3bc2b4c6fa92cd99 >> c5c301635%7C0%7C0%7C637346470803922895&sdata=i4DfCW8EVUSAWnzb8Ql4jPjAOD5wp >> tfbaMrO8vKvtDc%3D&reserved=0 > > This is a good place for non-zero Eps, but does not cover ep0. > ep0 is special, it's not touched in these add/drop endpoint or check bandwidth functions. ep0 ring is allocated earlier during slot creation in xhci_alloc_virt_device() ... /* Allocate endpoint 0 ring */ dev->eps[0].ring = xhci_ring_alloc(xhci, 2, 1, TYPE_CTRL, 0, flags); and for debugfs ep00 is added manually together with the slot xhci_debugfs_create_slot() ... xhci_debugfs_create_ring_dir(xhci, &dev->eps[0].ring, "ep00", priv->root); So regarding ep0 the change should be ok. -Mathias
