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usb: dwc3: gadget: remove wait_end_transfer

PATCH New Felipe Balbi 1 participant 1 message Jan 21, 2019 USB

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Felipe Balbi

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PATCH 10/14 usb: dwc3: gadget: remove wait_end_transfer

Hi

Quoted 50 lines · Felipe Balbi

Hi,

Quoted 47 lines · Felipe Balbi

Hi again,

Felipe Balbi <[email protected]> writes:

<snip>

Quoted 2 lines

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:

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;

[...]
}

Quoted 4 lines
Quoted 2 lines

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?

The following changes since commit 87b6d2c56825c3119a0e64cc208ae6d795810a2e:

usb: dwc2: gadget: Fix Remote Wakeup interrupt bit clearing (2019-01-17 15:56:53 +0200)

are available in the Git repository at:

git://git.kernel.org/pub/scm/linux/kernel/git/balbi/usb.git dwc3/fix-cancellation

for you to fetch changes up to 4cae1d5786f8ffdc4c7d840fd7e01580cee3c4ad:

usb: dwc3: gadget: remove DWC3_EP_END_TRANSFER_PENDING (2019-01-21 13:08:44 +0200)

----------------------------------------------------------------
Felipe Balbi (4):
usb: dwc3: gadget: clear DWC3_EP_TRANSFER_STARTED on cmd complete
usb: dwc3: gadget: don't use resource_index as a flag
usb: dwc3: gadget: early giveback if End Transfer already completed
usb: dwc3: gadget: remove DWC3_EP_END_TRANSFER_PENDING

 drivers/usb/dwc3/core.h   |  1 -
 drivers/usb/dwc3/gadget.c | 36 +++++++++++++-----------------------
 drivers/usb/dwc3/trace.h  |  3 +--
 3 files changed, 14 insertions(+), 26 deletions(-)

Thanks