This issue was found at android12 MTP.
1. MTP submit many out urb request.
2. Cancel left requests (>20) when enough data get from host
3. Send ACK by IN endpoint.
4. MTP submit new out urb request.
5. 4's urb never complete.

TRACE LOG:

MtpServer-2157    [000] d..3  1287.150391: cdns3_ep_dequeue: ep1out: req: 00000000299e6836, req buff 000000009df42287, length: 0/16384 zsi, status: -115, trb: [start:87, end:87: virt addr 0x80004000ffd50420], flags:1 SID: 0
MtpServer-2157    [000] d..3  1287.150410: cdns3_gadget_giveback: ep1out: req: 00000000299e6836, req buff 000000009df42287, length: 0/16384 zsi, status: -104, trb: [start:87, end:87: virt addr 0x80004000ffd50420], flags:0 SID: 0
MtpServer-2157    [000] d..3  1287.150433: cdns3_ep_dequeue: ep1out: req: 0000000080b7bde6, req buff 000000009ed5c556, length: 0/16384 zsi, status: -115, trb: [start:88, end:88: virt addr 0x80004000ffd5042c], flags:1 SID: 0
MtpServer-2157    [000] d..3  1287.150446: cdns3_gadget_giveback: ep1out: req: 0000000080b7bde6, req buff 000000009ed5c556, length: 0/16384 zsi, status: -104, trb: [start:88, end:88: virt addr 0x80004000ffd5042c], flags:0 SID: 0
	....
MtpServer-2157    [000] d..1  1293.630410: cdns3_alloc_request: ep1out: req: 00000000afbccb7d, req buff 0000000000000000, length: 0/0 zsi, status: 0, trb: [start:0, end:0: virt addr (null)], flags:0 SID: 0
MtpServer-2157    [000] d..2  1293.630421: cdns3_ep_queue: ep1out: req: 00000000afbccb7d, req buff 00000000871caf90, length: 0/512 zsi, status: -115, trb: [start:0, end:0: virt addr (null)], flags:0 SID: 0
MtpServer-2157    [000] d..2  1293.630445: cdns3_wa1: WA1: ep1out set guard
MtpServer-2157    [000] d..2  1293.630450: cdns3_wa1: WA1: ep1out restore cycle bit
MtpServer-2157    [000] d..2  1293.630453: cdns3_prepare_trb: ep1out: trb 000000007317b3ee, dma buf: 0xffd5bc00, size: 512, burst: 128 ctrl: 0x00000424 (C=0, T=0, ISP, IOC, Normal) SID:0 LAST_SID:0
MtpServer-2157    [000] d..2  1293.630460: cdns3_doorbell_epx: ep1out, ep_trbaddr ffd50414
	....
irq/241-5b13000-2154    [000] d..1  1293.680849: cdns3_epx_irq: IRQ for ep1out: 01000408 ISP , ep_traddr: ffd508ac ep_last_sid: 00000000 use_streams: 0
irq/241-5b13000-2154    [000] d..1  1293.680858: cdns3_complete_trb: ep1out: trb 0000000021a11b54, dma buf: 0xffd50420, size: 16384, burst: 128 ctrl: 0x00001810 (C=0, T=0, CHAIN, LINK) SID:0 LAST_SID:0
irq/241-5b13000-2154    [000] d..1  1293.680865: cdns3_request_handled: Req: 00000000afbccb7d not handled, DMA pos: 185, ep deq: 88, ep enq: 185, start trb: 184, end trb: 184

Actually DMA pos already bigger than previous submit request afbccb7d's TRB (184-184). The reason of (not handled) is that deq position is wrong.

The TRB link is below when irq happen.

	DEQ LINK LINK LINK LINK LINK .... TRB(afbccb7d):START  DMA(EP_TRADDR).

Original code check LINK TRB, but DEQ just move one step.

	LINK DEQ LINK LINK LINK LINK .... TRB(afbccb7d):START  DMA(EP_TRADDR).

This patch skip all LINK TRB and sync DEQ to trb's start.

	LINK LINK LINK LINK LINK .... DEQ = TRB(afbccb7d):START  DMA(EP_TRADDR).
Acked-by: Peter Chen <peter.chen@kernel.org>
Cc: stable <stable@vger.kernel.org>
Signed-off-by: Frank Li <Frank.Li@nxp.com>
Signed-off-by: Jun Li <jun.li@nxp.com>
Link: https://lore.kernel.org/r/20211130154239.8029-1-Frank.Li@nxp.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>