Hi Anurag, On 8/17/2018 5:25 AM, Anurag Kumar Vulisha wrote: > Availability of TRB's are calculated using dwc3_calc_trbs_left(), which > determines available TRB's based on the HWO bit set in a TRB. > > __dwc3_prepare_one_trb() is called with a TRB which needs to be prepared > for transfer. This __dwc3_prepare_one_trb() calls dwc3_calc_trbs_left() > to determine total available TRBs and set IOC bit if the total available > TRBs are zero. Since the present working TRB(which is passed as an > argument to __dwc3_prepare_one_trb() ) doesn't have HWO bit already set, > there are chances where dwc3_calc_trbs_left() wrongly calculates this > present working TRB as free(since the HWO bit is not yet set). This could > be a problem. This patch correct this issue by setting HWO bit before > calling dwc3_calc_trbs_left() > > Signed-off-by: Anurag Kumar Vulisha <anurag.kumar.vulisha@xxxxxxxxxx> > --- > Changes in v2: > 1. Changed the commit message > --- > drivers/usb/dwc3/gadget.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c > index 69bf137..f73d219 100644 > --- a/drivers/usb/dwc3/gadget.c > +++ b/drivers/usb/dwc3/gadget.c > @@ -990,6 +990,8 @@ static void __dwc3_prepare_one_trb(struct dwc3_ep *dep, struct dwc3_trb *trb, > trb->ctrl |= DWC3_TRB_CTRL_ISP_IMI; > } > > + trb->ctrl |= DWC3_TRB_CTRL_HWO; > + > if ((!no_interrupt && !chain) || > (dwc3_calc_trbs_left(dep) == 0)) > trb->ctrl |= DWC3_TRB_CTRL_IOC; > @@ -1000,8 +1002,6 @@ static void __dwc3_prepare_one_trb(struct dwc3_ep *dep, struct dwc3_trb *trb, > if (usb_endpoint_xfer_bulk(dep->endpoint.desc) && dep->stream_capable) > trb->ctrl |= DWC3_TRB_CTRL_SID_SOFN(stream_id); > > - trb->ctrl |= DWC3_TRB_CTRL_HWO; > - > trace_dwc3_prepare_trb(dep, trb); > } > How do you reproduce this issue? We should not set HWO before setting other trb->ctrl bits. Can you provide a driver tracepoint? If there's an issue with the check if ((!no_interrupt && !chain) || dwc3_calc_trbs_left == 0), then we may need to fix the check there. BR, Thinh
