usb: xhci: Handle bogus TRB pointers in Missed Service Error events

xHCI 1.0 allowed these pointers to be zero. Some Intel chipsets from the
era usually set it to zero, but sometimes (apparently) to the next TRB
after the one referenced by the previous transfer event on the endpoint.

Usually that's indeed the missed TD, but it may also be the last TRB of
a two-TRB TD already completed with Short Packet on its first TRB. Then
the driver skips all pending TDs, failing to find a match.

When handling Missed Service Error, scan TD list twice and only really
skip TDs in the second pass if the first pass found a match. This won't
catch bogus pointers to wrong TDs, but such a bug would be practically
impossible to detect automatically and isn't known to exist.

Reported-by: Bart Nagel <bart@tremby.net>
Closes: https://lore.kernel.org/linux-usb/al_hchyOdPoPWKEo@spiral/
Suggested-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Fixes: d0b619599e52 ("usb: xhci: Expedite skipping missed isoch TDs on modern HCs")
Cc: stable@vger.kernel.org
Signed-off-by: Michal Pecio <michal.pecio@gmail.com>
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://patch.msgid.link/20260806142113.2436238-18-mathias.nyman@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

0 files changed, 0 insertions, 0 deletions