6.15-stable review patch. If anyone has any objections, please let me know.
------------------
From: SCHNEIDER Johannes johannes.schneider@leica-geosystems.com
commit 80e08394377559ed5a2ccadd861e62d24b826911 upstream.
Commit 96c7bf8f6b3e ("usb: dwc3: gadget: Cleanup SG handling") updated the TRB reclaim path to use the TRB CHN (Chain) bit to determine whether a TRB was part of a chain. However, this inadvertently changed the behavior of reclaiming the final TRB in some scatter-gather or short transfer cases.
In particular, if the final TRB did not have the CHN bit set, the cleanup path could incorrectly skip clearing the HWO (Hardware Own) bit, leaving stale TRBs in the ring. This resulted in broken data transfer completions in userspace, notably for MTP over FunctionFS.
Fix this by unconditionally clearing the HWO bit during TRB reclaim, regardless of the CHN bit state. This restores correct behavior especially for transfers that require ZLPs or end on non-CHN TRBs.
Fixes: 61440628a4ff ("usb: dwc3: gadget: Cleanup SG handling") Signed-off-by: Johannes Schneider johannes.schneider@leica-geosystems.com Acked-by: Thinh Nguyen Thinh.Nguyen@synopsys.com Cc: stable stable@kernel.org Link: https://lore.kernel.org/r/AM8PR06MB7521A29A8863C838B54987B6BC7BA@AM8PR06MB75... Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/usb/dwc3/gadget.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c index b6b63b530148..74968f93d4a3 100644 --- a/drivers/usb/dwc3/gadget.c +++ b/drivers/usb/dwc3/gadget.c @@ -3516,7 +3516,7 @@ static int dwc3_gadget_ep_reclaim_completed_trb(struct dwc3_ep *dep, * We're going to do that here to avoid problems of HW trying * to use bogus TRBs for transfers. */ - if (chain && (trb->ctrl & DWC3_TRB_CTRL_HWO)) + if (trb->ctrl & DWC3_TRB_CTRL_HWO) trb->ctrl &= ~DWC3_TRB_CTRL_HWO;
/*