Tejas Joglekar <tejas.joglekar@xxxxxxxxxxxx> writes:
> In stream mode, when fast-forwarding TRBs, the stream number
> is not cleared causing the new stream to not get assigned. So
> we don't want controller to carry on transfers when short packet
> is received. So disable the CSP for stream capable endpoint.
>
> This is based on the 3.30a Programming guide, where table 3-1
> device descriptor structure field definitions says for CSP bit
> If this bit is 0, the controller generates an XferComplete event
> and remove the stream. So if we keep CSP as 1 then switching between
> streams would not happen as in stream mode, when fast-forwarding
> TRBs, the stream number is not cleared causing the new stream to not get
> assigned.
>
> Signed-off-by: Tejas Joglekar <joglekar@xxxxxxxxxxxx>
> ---
> drivers/usb/dwc3/gadget.c | 10 ++++++++--
> 1 file changed, 8 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
> index f1089ec..0d2afc1 100644
> --- a/drivers/usb/dwc3/gadget.c
> +++ b/drivers/usb/dwc3/gadget.c
> @@ -986,9 +986,15 @@ static void __dwc3_prepare_one_trb(struct dwc3_ep *dep, struct dwc3_trb *trb,
> usb_endpoint_type(dep->endpoint.desc));
> }
>
> - /* always enable Continue on Short Packet */
> + /*
> + * Enable Continue on Short Packet
> + * when endpoint is not a stream capable
> + */
> if (usb_endpoint_dir_out(dep->endpoint.desc)) {
> - trb->ctrl |= DWC3_TRB_CTRL_CSP;
> + if (dep->stream_capable)
> + trb->ctrl &= ~DWC3_TRB_CTRL_CSP;
Is this necessary? Or would it be enough to have this as:
if (!dep->stream_capable)
trb->ctrl |= DWC3_TRB_CTRL_CSP;
--
balbi
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