[PATCH 6.1 41/71] xhci: handle isoc Babble and Buffer Overrun events properly

Sasha Levin
2024-03-13T16:40:48Z

From: Michal Pecio <michal.pecio@gmail.com>

[ Upstream commit 7c4650ded49e5b88929ecbbb631efb8b0838e811 ]

xHCI 4.9 explicitly forbids assuming that the xHC has released its
ownership of a multi-TRB TD when it reports an error on one of the
early TRBs. Yet the driver makes such assumption and releases the TD,
allowing the remaining TRBs to be freed or overwritten by new TDs.

The xHC should also report completion of the final TRB due to its IOC
flag being set by us, regardless of prior errors. This event cannot
be recognized if the TD has already been freed earlier, resulting in
"Transfer event TRB DMA ptr not part of current TD" error message.

Fix this by reusing the logic for processing isoc Transaction Errors.
This also handles hosts which fail to report the final completion.

Fix transfer length reporting on Babble errors. They may be caused by
device malfunction, no guarantee that the buffer has been filled.

Signed-off-by: Michal Pecio <michal.pecio@gmail.com>
Cc: stable@vger.kernel.org
Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Link: https://lore.kernel.org/r/20240125152737.2983959-5-mathias.nyman@linux.intel.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/usb/host/xhci-ring.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
index e4441a71368e5..239b5edee3268 100644
--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c
@@ -2381,9 +2381,13 @@ static int process_isoc_td(struct xhci_hcd *xhci, struct xhci_virt_ep *ep,
case COMP_BANDWIDTH_OVERRUN_ERROR:
frame->status = -ECOMM;
break;
- case COMP_ISOCH_BUFFER_OVERRUN:
case COMP_BABBLE_DETECTED_ERROR:
+ sum_trbs_for_length = true;
+ fallthrough;
+ case COMP_ISOCH_BUFFER_OVERRUN:
frame->status = -EOVERFLOW;
+ if (ep_trb != td->last_trb)
+ td->error_mid_td = true;
break;
case COMP_INCOMPATIBLE_DEVICE_ERROR:
case COMP_STALL_ERROR:
--
2.43.0