[v2,0/4] usb: dwc3: gadget: Improve isoc starting mechanism

Message

Thinh Nguyen March 29, 2020, 11:12 p.m. UTC

Currently we use the "retry" method to issue START_TRANSFER command multiple
times, each with a next interval. There's been report that 5 number of retries
may not be enough. See https://lkml.org/lkml/2019/11/11/535

We could increase the number of retries. However, that also may not be enough
depending on different system latency. It is not often that the latency is
higher than 5 isoc intervals. If it goes beyond 5 intervals, let's restart the
whole process again.


Changes in v2:
 - Include patch "usb: dwc3: gadget: WARN on no-resource status" to this series

Thinh Nguyen (4):
  usb: dwc3: gadget: Properly handle failed kick_transfer
  usb: dwc3: gadget: Store resource index of start cmd
  usb: dwc3: gadget: Issue END_TRANSFER to retry isoc transfer
  usb: dwc3: gadget: WARN on no-resource status

 drivers/usb/dwc3/gadget.c | 71 +++++++++++++++++++++++++++++++++++++++--------
 1 file changed, 59 insertions(+), 12 deletions(-)

Comments

Felipe Balbi March 30, 2020, 8:15 a.m. UTC | #1

Thinh Nguyen <[e-mail]> writes:

> Currently we use the "retry" method to issue START_TRANSFER command multiple
> times, each with a next interval. There's been report that 5 number of retries
> may not be enough. See https://lkml.org/lkml/2019/11/11/535
>
> We could increase the number of retries. However, that also may not be enough
> depending on different system latency. It is not often that the latency is
> higher than 5 isoc intervals. If it goes beyond 5 intervals, let's restart the
> whole process again.
>
>
> Changes in v2:
>  - Include patch "usb: dwc3: gadget: WARN on no-resource status" to this series
>
> Thinh Nguyen (4):
>   usb: dwc3: gadget: Properly handle failed kick_transfer
>   usb: dwc3: gadget: Store resource index of start cmd
>   usb: dwc3: gadget: Issue END_TRANSFER to retry isoc transfer
>   usb: dwc3: gadget: WARN on no-resource status

all in testing/next now