[10/14] usb: dwc3: gadget: remove wait_end_transfer

Hi Felipe,

On 1/21/2019 4:15 AM, Felipe Balbi wrote:

Hi

Felipe Balbi [off-list ref] writes:

quoted

Hi,

Felipe Balbi [off-list ref] writes:

quoted

Hi again,

Felipe Balbi [off-list ref] writes:

<snip>

quoted

Try to dequeue a request that was already completed. Odd. Why are we
missing a call to giveback??

Got a little more information:

    file-storage-3982  [006] d...   131.010663: dwc3_ep_queue: ep1in: req 00000000eccaa10f length 0/16384 zsI ==> -115
    file-storage-3982  [006] d...   131.010667: dwc3_prepare_trb: ep1in: trb 000000002ab8a1f9 buf 00000000bde24000 size 16384 ctrl 00000811 (Hlcs:sC:normal)
    file-storage-3982  [006] d...   131.010674: dwc3_gadget_ep_cmd: ep1in: cmd 'Update Transfer' [30007] params 00000000 00000000 00000000 --> status: Successful
     irq/16-dwc3-3983  [004] d...   131.010942: dwc3_event: event (00004086): ep1in: Transfer In Progress [0] (sIm)
     irq/16-dwc3-3983  [004] d...   131.010942: dwc3_complete_trb: ep1in: trb 00000000426cd8cf buf 00000000bde20000 size 0 ctrl 00000810 (hlcs:sC:normal)
     irq/16-dwc3-3983  [004] d...   131.010944: dwc3_gadget_giveback: ep1in: req 00000000f7765e56 length 16384/16384 zsI ==> 0
    file-storage-3982  [006] d...   131.010994: dwc3_ep_queue: ep1in: req 00000000f7765e56 length 0/16384 zsI ==> -115
    file-storage-3982  [006] d...   131.010998: dwc3_prepare_trb: ep1in: trb 0000000065d9143d buf 00000000bde28000 size 16384 ctrl 00000811 (Hlcs:sC:normal)
    file-storage-3982  [006] d...   131.011005: dwc3_gadget_ep_cmd: ep1in: cmd 'Update Transfer' [30007] params 00000000 00000000 00000000 --> status: Successful
     irq/16-dwc3-3983  [004] d...   131.065517: dwc3_event: event (00000001): Disconnect: [U0]
    file-storage-3982  [006] ....   131.065558: dwc3_ep_dequeue: ep1in: req 00000000f7765e56 length 0/16384 zsI ==> -115
    file-storage-3982  [006] d...   131.065687: dwc3_gadget_ep_cmd: ep1in: cmd 'End Transfer' [30d08] params 00000000 00000000 00000000 --> status: Successful
     irq/16-dwc3-3983  [004] d...   131.065729: dwc3_event: event (080301c6): ep1in: Endpoint Command Complete
     irq/16-dwc3-3983  [004] d...   131.065731: dwc3_gadget_giveback: ep1in: req 00000000f7765e56 length 0/16384 zsI ==> -104
    file-storage-3982  [006] ....   131.065766: dwc3_ep_dequeue: ep1in: req 00000000eccaa10f length 0/16384 zsI ==> -115
     irq/16-dwc3-3983  [004] d...   135.071714: dwc3_event: event (00000101): Reset [U0]
     irq/16-dwc3-3983  [004] d...   135.126440: dwc3_event: event (00000201): Connection Done [U0]

From this snippet above it seems like we got End Transfer completed
*before* we tried to dequeue the request. This is a race in the driver,
since it will wait for End Transfer complete forever :-p We can see that
ep_dequeue won't send a new End Transfer unless it's necessary:

Right. That was what I try to point in my previous reply.

quoted

quoted

static void dwc3_stop_active_transfer(struct dwc3_ep *dep, bool force)
{
	struct dwc3 *dwc = dep->dwc;
	struct dwc3_gadget_ep_cmd_params params;
	u32 cmd;
	int ret;

	if ((dep->flags & DWC3_EP_END_TRANSFER_PENDING) ||
	    !dep->resource_index)
		return;
[...]
}

So this will wait forever. Here's a patch that takes into consideration
this possibility:

a version that compiles now (#facepalm):

I've prepared a branch with a few patches on top of my testing/fixes to
test this out. Seems to work fine on my end. Can you try with your test
setup?

I think you need to fix this:

        /*


Other than that, these changes seem to fix the issue.

Thanks,
Thinh

diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index 1b7c44271b11..73e3a402f63d 100644
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c

@@ -2621,7 +2621,7 @@ static void dwc3_stop_active_transfer(struct

dwc3_ep *dep, bool force)
        u32 cmd;
        int ret;
 
-       if (dep->flags & DWC3_EP_TRANSFER_STARTED)
+       if (!(dep->flags & DWC3_EP_TRANSFER_STARTED))
                return;