4.4-stable review patch. If anyone has any objections, please let me know.
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From: William Wu william.wu@rock-chips.com
[ Upstream commit 70c3c8cb83856758025c2a211dd022bc0478922a ]
If isoc split in transfer with no data (the length of DATA0 packet is zero), we can't simply return immediately. Because the DATA0 can be the first transaction or the second transaction for the isoc split in transaction. If the DATA0 packet with no data is in the first transaction, we can return immediately. But if the DATA0 packet with no data is in the second transaction of isoc split in transaction sequence, we need to increase the qtd->isoc_frame_index and giveback urb to device driver if needed, otherwise, the MDATA packet will be lost.
A typical test case is that connect the dwc2 controller with an usb hs Hub (GL852G-12), and plug an usb fs audio device (Plantronics headset) into the downstream port of Hub. Then use the usb mic to record, we can find noise when playback.
In the case, the isoc split in transaction sequence like this:
- SSPLIT IN transaction - CSPLIT IN transaction - MDATA packet (176 bytes) - CSPLIT IN transaction - DATA0 packet (0 byte)
This patch use both the length of DATA0 and qtd->isoc_split_offset to check if the DATA0 is in the second transaction.
Tested-by: Gevorg Sahakyan sahakyan@synopsys.com Tested-by: Heiko Stuebner heiko@sntech.de Acked-by: Minas Harutyunyan hminas@synopsys.com> Signed-off-by: William Wu william.wu@rock-chips.com Signed-off-by: Felipe Balbi felipe.balbi@linux.intel.com Signed-off-by: Sasha Levin alexander.levin@microsoft.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/usb/dwc2/hcd_intr.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-)
--- a/drivers/usb/dwc2/hcd_intr.c +++ b/drivers/usb/dwc2/hcd_intr.c @@ -931,9 +931,8 @@ static int dwc2_xfercomp_isoc_split_in(s frame_desc = &qtd->urb->iso_descs[qtd->isoc_frame_index]; len = dwc2_get_actual_xfer_length(hsotg, chan, chnum, qtd, DWC2_HC_XFER_COMPLETE, NULL); - if (!len) { + if (!len && !qtd->isoc_split_offset) { qtd->complete_split = 0; - qtd->isoc_split_offset = 0; return 0; }