Hi Minas, ? 2017?11?06? 17:28, Minas Harutyunyan ??: > Hi, > > On 11/6/2017 12:46 PM, William Wu wrote: >> The actual_length in dwc2_hcd_urb structure is used >> to indicate the total data length transferred so far, >> but in dwc2_update_isoc_urb_state(), it just updates >> the actual_length of isoc frame, and don't update the >> urb actual_length at the same time, this will cause >> device drivers working error which depend on the urb >> actual_length. >> >> we can easily find this issue if use an USB camera? >> the userspace use libusb to get USB data from kernel >> via devio driver.In usb devio driver, processcompl() >> function will process urb complete and copy data to >> userspace depending on urb actual_length. >> >> Let's update the urb actual_length if the isoc frame >> is valid. >> >> Signed-off-by: William Wu <william.wu at rock-chips.com> >> --- >> drivers/usb/dwc2/hcd_intr.c | 2 ++ >> 1 file changed, 2 insertions(+) >> >> diff --git a/drivers/usb/dwc2/hcd_intr.c b/drivers/usb/dwc2/hcd_intr.c >> index 28a8210..01b1e13 100644 >> --- a/drivers/usb/dwc2/hcd_intr.c >> +++ b/drivers/usb/dwc2/hcd_intr.c >> @@ -580,6 +580,7 @@ static enum dwc2_halt_status dwc2_update_isoc_urb_state( >> frame_desc->status = 0; >> frame_desc->actual_length = dwc2_get_actual_xfer_length(hsotg, >> chan, chnum, qtd, halt_status, NULL); >> + urb->actual_length += frame_desc->actual_length; >> break; >> case DWC2_HC_XFER_FRAME_OVERRUN: >> urb->error_count++; >> @@ -599,6 +600,7 @@ static enum dwc2_halt_status dwc2_update_isoc_urb_state( >> frame_desc->status = -EPROTO; >> frame_desc->actual_length = dwc2_get_actual_xfer_length(hsotg, >> chan, chnum, qtd, halt_status, NULL); >> + urb->actual_length += frame_desc->actual_length; >> >> /* Skip whole frame */ >> if (chan->qh->do_split && >> > According urb description in usb.h urb->actual_length used for non-iso > transfers: > > "@actual_length: This is read in non-iso completion functions, and ... > > * ISO transfer status is reported in the status and actual_length fields > * of the iso_frame_desc array, ...." Yes, urb->actual_length is used for non-iso transfers. And for ISO transfer, the most usb class drivers can only use iso frame status and actual_length to handle usb data, like: kernel v4.4 drivers/media/usb/uvc/uvc_video.c But the usb devio driver really need the urb actual_length in the processcompl() if handle ISO transfer, just as I mentioned in the commit message. And I also found the same issue on raspberrypi board: https://github.com/raspberrypi/linux/issues/903 So do you think we need to fix the usb devio driver, rather than fix dwc2? I think maybe we can use urb actual length for ISO transfer, it seems that don't cause any side-effect. > > Thanks, > Minas > > > > > > -- ??? William.Wu ?????????????89????A?21?? No.21 Building, A District, No.89,software Boulevard Fuzhou,Fujian, PRC ??: 13685012275 ??: 0591-83991906-8520 ??:wulf at rock-chips.com
