Hi Anurag, On 9/7/2018 6:14 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() Please revise your commit message to reflect your new change. > > Signed-off-by: Anurag Kumar Vulisha <anurag.kumar.vulisha@xxxxxxxxxx> > Reviewed-by: Thinh Nguyen <thinhn@xxxxxxxxxxxx> > --- > Changes in v3: > 1. Corrected the logic for setting HWO bit as suggested by "Thinh Nguyen" > > Changes in v2: > 1. Changed the commit message > --- > drivers/usb/dwc3/gadget.c | 6 +++--- > 1 file changed, 3 insertions(+), 3 deletions(-) > > diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c > index 032ea7d..8a1622b 100644 > --- a/drivers/usb/dwc3/gadget.c > +++ b/drivers/usb/dwc3/gadget.c > @@ -911,8 +911,6 @@ static void __dwc3_prepare_one_trb(struct dwc3_ep *dep, struct dwc3_trb *trb, > struct usb_gadget *gadget = &dwc->gadget; > enum usb_device_speed speed = gadget->speed; > > - dwc3_ep_inc_enq(dep); > - > trb->size = DWC3_TRB_SIZE_LENGTH(length); > trb->bpl = lower_32_bits(dma); > trb->bph = upper_32_bits(dma); > @@ -991,7 +989,7 @@ static void __dwc3_prepare_one_trb(struct dwc3_ep *dep, struct dwc3_trb *trb, > } > > if ((!no_interrupt && !chain) || > - (dwc3_calc_trbs_left(dep) == 0)) > + (dwc3_calc_trbs_left(dep) == 1)) > trb->ctrl |= DWC3_TRB_CTRL_IOC; > > if (chain) > @@ -1002,6 +1000,8 @@ static void __dwc3_prepare_one_trb(struct dwc3_ep *dep, struct dwc3_trb *trb, > > trb->ctrl |= DWC3_TRB_CTRL_HWO; > > + dwc3_ep_inc_enq(dep); > + > trace_dwc3_prepare_trb(dep, trb); > } > BR, Thinh
