2023-11-22 09:12:23

by Uttkarsh Aggarwal

Subject: [RFC] usb: dwc: ep0: Use -ESHUTDOWN in dwc3_ep0_stall_restart

Current implementation blocks the running operations when Plug-out and
Plug-In is performed continuously, process gets stuck in
dwc3_thread_interrupt().

Code Flow:

CPU1

->Gadget_start
->dwc3_interrupt
->dwc3_thread_interrupt
->dwc3_process_event_buf
->dwc3_process_event_entry
->dwc3_endpoint_interrupt
->dwc3_ep0_interrupt
->dwc3_ep0_inspect_setup
->dwc3_ep0_stall_and_restart

By this time if pending_list is not empty, it will get the next request
on the given list and calls dwc3_gadget_giveback which will unmap request
and call its complete() callback to notify upper layers that it has
completed. Currently dwc3_gadget_giveback status is set to-ECONNRESET,
whereas it should be -ESHUTDOWN.

Cc: <[email protected]>
Fixes: d742220b3577 ("usb: dwc3: ep0: giveback requests on stall_and_restart")
Signed-off-by: Uttkarsh Aggarwal <[email protected]>
---
drivers/usb/dwc3/ep0.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/usb/dwc3/ep0.c b/drivers/usb/dwc3/ep0.c
index b94243237293..8317fedda1c0 100644
--- a/drivers/usb/dwc3/ep0.c
+++ b/drivers/usb/dwc3/ep0.c
@@ -238,7 +238,7 @@ void dwc3_ep0_stall_and_restart(struct dwc3 *dwc)
struct dwc3_request *req;

req = next_request(&dep->pending_list);
- dwc3_gadget_giveback(dep, req, -ECONNRESET);
+ dwc3_gadget_giveback(dep, req, -ESHUTDOWN);
}

dwc->eps[0]->trb_enqueue = 0;
--
2.17.1

2023-12-05 01:44:04

by Thinh Nguyen

Subject: Re: [RFC] usb: dwc: ep0: Use -ESHUTDOWN in dwc3_ep0_stall_restart

On Wed, Nov 22, 2023, Uttkarsh Aggarwal wrote:
> Current implementation blocks the running operations when Plug-out and
> Plug-In is performed continuously, process gets stuck in
> dwc3_thread_interrupt().
>
> Code Flow:
>
> CPU1
>
> ->Gadget_start
> ->dwc3_interrupt
> ->dwc3_thread_interrupt
> ->dwc3_process_event_buf
> ->dwc3_process_event_entry
> ->dwc3_endpoint_interrupt
> ->dwc3_ep0_interrupt
> ->dwc3_ep0_inspect_setup
> ->dwc3_ep0_stall_and_restart
>
> By this time if pending_list is not empty, it will get the next request
> on the given list and calls dwc3_gadget_giveback which will unmap request
> and call its complete() callback to notify upper layers that it has
> completed. Currently dwc3_gadget_giveback status is set to-ECONNRESET,
> whereas it should be -ESHUTDOWN.
>
> Cc: <[email protected]>
> Fixes: d742220b3577 ("usb: dwc3: ep0: giveback requests on stall_and_restart")
> Signed-off-by: Uttkarsh Aggarwal <[email protected]>
> ---
> drivers/usb/dwc3/ep0.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/usb/dwc3/ep0.c b/drivers/usb/dwc3/ep0.c
> index b94243237293..8317fedda1c0 100644
> --- a/drivers/usb/dwc3/ep0.c
> +++ b/drivers/usb/dwc3/ep0.c
> @@ -238,7 +238,7 @@ void dwc3_ep0_stall_and_restart(struct dwc3 *dwc)
> struct dwc3_request *req;
>
> req = next_request(&dep->pending_list);
> - dwc3_gadget_giveback(dep, req, -ECONNRESET);
> + dwc3_gadget_giveback(dep, req, -ESHUTDOWN);

There are other conditions which should return -ECONNRESET (e.g. invalid
length, direction, got cancelled). For the particular condition that you
want for -ESHUTDOWN, I think you can use the dwc->connected field to
check for that.

BR,
Thinh

> }
>
> dwc->eps[0]->trb_enqueue = 0;
> --
> 2.17.1
>