Re: [PATCH] usb: dwc2: gadget: fix ISOC frame overflow handling
From: Minas Harutyunyan
Date: Fri Nov 09 2018 - 03:43:33 EST
Hi John,
On 11/8/2018 9:37 PM, John Keeping wrote:
> Hi Minas,
>
> On Mon, 5 Nov 2018 08:28:07 +0000
> Minas Harutyunyan <minas.harutyunyan@xxxxxxxxxxxx> wrote:
>
>> On 10/23/2018 5:43 PM, John Keeping wrote:
>>> By clearing the overrun flag as soon as the target frame is next
>>> incremented, we can end up incrementing the target frame more than
>>> expected in dwc2_gadget_handle_ep_disabled() when the endpoint's
>>> interval is greater than 1. This happens if the target frame has
>>> just wrapped at the point when the endpoint is disabled and the
>>> frame number has not yet done so.
>>>
>>> Instead, wait until the frame number also wraps and then clear the
>>> overrun flag.
>>>
>>> Signed-off-by: John Keeping <john@xxxxxxxxxxxx>
>>> ---
>>> drivers/usb/dwc2/gadget.c | 2 +-
>>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/usb/dwc2/gadget.c b/drivers/usb/dwc2/gadget.c
>>> index 2d6d2c8244de..8da2c052dfa1 100644
>>> --- a/drivers/usb/dwc2/gadget.c
>>> +++ b/drivers/usb/dwc2/gadget.c
>>> @@ -117,7 +117,7 @@ static inline void
>>> dwc2_gadget_incr_frame_num(struct dwc2_hsotg_ep *hs_ep) if
>>> (hs_ep->target_frame > DSTS_SOFFN_LIMIT) { hs_ep->frame_overrun =
>>> true; hs_ep->target_frame &= DSTS_SOFFN_LIMIT;
>>> - } else {
>>> + } else if (hs_ep->parent->frame_number <
>>> hs_ep->target_frame) { hs_ep->frame_overrun = false;
>>> }
>>> }
>>>
>> Did you tested mentioned by you scenario? If you see issue can you
>> provide debug log and point the issue line in the log.
>
> It only reproduces very occasionally so it's difficult to capture a full
> debug log containing the error.
>
> I applied this patch to capture logging specifically around this
> scenario:
>
> -- >8 --
> diff --git a/drivers/usb/dwc2/gadget.c b/drivers/usb/dwc2/gadget.c
> index 220c0f9b89b0..3770b9d3b523 100644
> --- a/drivers/usb/dwc2/gadget.c
> +++ b/drivers/usb/dwc2/gadget.c
> @@ -2722,13 +2722,20 @@ static void dwc2_gadget_handle_ep_disabled(struct dwc2_hsotg_ep *hs_ep)
> }
>
> do {
> + unsigned int target_frame = hs_ep->target_frame;
> + bool frame_overrun = hs_ep->frame_overrun;
> +
> hs_req = get_ep_head(hs_ep);
> if (hs_req)
> dwc2_hsotg_complete_request(hsotg, hs_ep, hs_req,
> -ENODATA);
> +
> dwc2_gadget_incr_frame_num(hs_ep);
> /* Update current frame number value. */
> hsotg->frame_number = dwc2_hsotg_read_frameno(hsotg);
> +
> + dev_warn(hsotg->dev, "%s: expiring request frame_number=0x%04x target_frame=0x%04x overrun=%u\n",
> + __func__, hsotg->frame_number, target_frame, frame_overrun);
> } while (dwc2_gadget_target_frame_elapsed(hs_ep));
>
> dwc2_gadget_start_next_request(hs_ep);
> -- 8< --
>
> and I captured this log (the first entry is a separate error and then
> the remaining ones show this bug being triggered):
>
> [ 562.571227] dwc2 ff580000.usb: dwc2_gadget_handle_ep_disabled: expiring request frame_number=0x3eb9 target_frame=0x3ec0
> [ 562.611213] dwc2 ff580000.usb: dwc2_gadget_handle_ep_disabled: expiring request frame_number=0x3ff8 target_frame=0x0008
> [ 562.611219] dwc2 ff580000.usb: dwc2_gadget_handle_ep_disabled: expiring request frame_number=0x3ff8 target_frame=0x0010
> [ 562.611223] dwc2 ff580000.usb: dwc2_gadget_handle_ep_disabled: expiring request frame_number=0x3ff9 target_frame=0x0018
> [ 562.611228] dwc2 ff580000.usb: dwc2_gadget_handle_ep_disabled: expiring request frame_number=0x3ff9 target_frame=0x0020
> [ 562.611232] dwc2 ff580000.usb: dwc2_gadget_handle_ep_disabled: expiring request frame_number=0x3ff9 target_frame=0x0028
> [ 562.611236] dwc2 ff580000.usb: dwc2_gadget_handle_ep_disabled: expiring request frame_number=0x3ff9 target_frame=0x0030
> [ 562.611240] dwc2 ff580000.usb: dwc2_gadget_handle_ep_disabled: expiring request frame_number=0x3ff9 target_frame=0x0038
> [ 562.611244] dwc2 ff580000.usb: dwc2_gadget_handle_ep_disabled: expiring request frame_number=0x3ff9 target_frame=0x0040
> [ 562.611249] dwc2 ff580000.usb: dwc2_gadget_handle_ep_disabled: expiring request frame_number=0x3ff9 target_frame=0x0048
> [ 562.611253] dwc2 ff580000.usb: dwc2_gadget_handle_ep_disabled: expiring request frame_number=0x3ff9 target_frame=0x0050
> [ 562.611257] dwc2 ff580000.usb: dwc2_gadget_handle_ep_disabled: expiring request frame_number=0x3ff9 target_frame=0x0058
> [ 562.611261] dwc2 ff580000.usb: dwc2_gadget_handle_ep_disabled: expiring request frame_number=0x3ff9 target_frame=0x0060
> [ 562.611265] dwc2 ff580000.usb: dwc2_gadget_handle_ep_disabled: expiring request frame_number=0x3ff9 target_frame=0x0068
> [ 562.611269] dwc2 ff580000.usb: dwc2_gadget_handle_ep_disabled: expiring request frame_number=0x3ff9 target_frame=0x0070
> [ 562.611274] dwc2 ff580000.usb: dwc2_gadget_handle_ep_disabled: expiring request frame_number=0x3ff9 target_frame=0x0078
> [ 562.611278] dwc2 ff580000.usb: dwc2_gadget_handle_ep_disabled: expiring request frame_number=0x3ff9 target_frame=0x0080
> [ 562.611282] dwc2 ff580000.usb: dwc2_gadget_handle_ep_disabled: expiring request frame_number=0x3ff9 target_frame=0x0088
> [ 562.611286] dwc2 ff580000.usb: dwc2_gadget_handle_ep_disabled: expiring request frame_number=0x3ff9 target_frame=0x0090
> [ 562.611290] dwc2 ff580000.usb: dwc2_gadget_handle_ep_disabled: expiring request frame_number=0x3ff9 target_frame=0x0098
> [ 562.611294] dwc2 ff580000.usb: dwc2_gadget_handle_ep_disabled: expiring request frame_number=0x3ff9 target_frame=0x00a0
>
According above patch in debug log should be printed overrun flag also.
Could you please resend log with this flag.
>
> This was on v4.19 with an additional patch to disable descriptor DMA
> because that seems to be causing problems on RK3288 although I haven't
> figured out exactly why it's a problem.
In which mode you run tests Slave or Buffer DMA?
>
>
> Regards,
> John
>
Thanks,
Minas