Dear Doug, 在 2018年05月02日 13:02, Doug Anderson 写道:
Hi, On Tue, May 1, 2018 at 8:04 PM, William Wu <william.wu@xxxxxxxxxxxxxx> wrote: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. Signed-off-by: William Wu <william.wu@xxxxxxxxxxxxxx> --- Changes in v2: - Modify the commit message drivers/usb/dwc2/hcd_intr.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/usb/dwc2/hcd_intr.c b/drivers/usb/dwc2/hcd_intr.c index 5e2378f..479f628 100644 --- a/drivers/usb/dwc2/hcd_intr.c +++ b/drivers/usb/dwc2/hcd_intr.c @@ -930,7 +930,7 @@ static int dwc2_xfercomp_isoc_split_in(struct dwc2_hsotg *hsotg, 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;I don't think my USB-fu is strong enough to do a real review of this patch, but one small nitpick is that you can remove "qtd->isoc_split_offset = 0" in the if test now. AKA: if (!len && !qtd->isoc_split_offset) { qtd->complete_split = 0; return 0; }
Yes, good idea! I will fix it in next patch. Thank you!
...since you only enter the "if" test now when isoc_split_offset is already 0... Hopefully John Youn will have some time to comment on this patch with more real USB knowledge... -Doug
Best regards, wulf
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