| From foo@baz Wed Aug 22 09:42:09 CEST 2018 |
| From: William Wu <william.wu@rock-chips.com> |
| Date: Fri, 11 May 2018 17:46:32 +0800 |
| Subject: usb: dwc2: fix isoc split in transfer with no data |
| |
| 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 |
| @@ -922,9 +922,8 @@ 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; |
| } |
| |