Hi Bin,
On 8/10/2018 12:05 PM, Bin Liu wrote:
> Hi Felipe,
>
> I noticed a regression on g_audio (uac2) with dwc3 udc on v4.14:
>
> - nosound in playback
> - playback can only play once, the following error happens from the 2nd
> playback
>
> aplay: set_params:1361: Unable to install hw params:
>
> A manual bisect tells the two issues are seperate and the regression
> happens in v4.11-rc2 with the following two patches.
>
> 40d829fb2ec63 ("usb: dwc3: gadget: Correct ISOC DATA PIDs for short packets")
>
> which cases the first no-sound issue.
>
> ep->mult is already 1 from g_audio, so mult-- leads to incorrect value.
> The following change solves it.
I believe v4.14.40 is missing this patch regarding that issue:
ec5bb87e4e2a ("usb: dwc3: gadget: Fix PCM1 for ISOC EP with ep->mult
less than 3")
>
> diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
> index f92e2f2c7fbe..758cc258895c 100644
> --- a/drivers/usb/dwc3/gadget.c
> +++ b/drivers/usb/dwc3/gadget.c
> @@ -930,10 +930,10 @@ static void __dwc3_prepare_one_trb(struct dwc3_ep *dep, struct dwc3_trb *trb,
> unsigned int mult = ep->mult - 1;
> unsigned int maxp = usb_endpoint_maxp(ep->desc);
>
> - if (length <= (2 * maxp))
> + if (mult && length <= (2 * maxp))
> mult--;
>
> - if (length <= maxp)
> + if (mult && length <= maxp)
> mult--;
>
> trb->size |= DWC3_TRB_SIZE_PCM1(mult);
>
> cf3113d893d4 ("usb: dwc3: gadget: properly increment dequeue pointer on ep_dequeue")
>
> which causes the multiple playback failure. The following hack covers it.
>
> diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
> index f92e2f2c7fbe..758cc258895c 100644
> --- a/drivers/usb/dwc3/gadget.c
> +++ b/drivers/usb/dwc3/gadget.c
> @@ -1411,7 +1411,7 @@ static int dwc3_gadget_ep_dequeue(struct usb_ep *ep,
> if (r == req) {
> /* wait until it is processed */
> dwc3_stop_active_transfer(dwc, dep->number, true);
> -
> +#if 0
> /*
> * If request was already started, this means we had to
> * stop the transfer. With that we also need to ignore
> @@ -1473,6 +1473,7 @@ static int dwc3_gadget_ep_dequeue(struct usb_ep *ep,
> dwc3_ep_inc_deq(dep);
> }
> }
> +#endif
> goto out1;
> }
> dev_err(dwc->dev, "request %pK was not queued to %s\n",
>
> With the two changes above, g_audio works fine with v4.14.40, but not with
> v4.18-rc7, in which the console is flooded with following message.
>
> u_audio_iso_complete: iso_complete status(-18) 0/256
>
Pierre Le Magourou attempted to fix the second issue with this patch
(though the patch may need rework):
https://patchwork.kernel.org/patch/10509639/
You can try it out. It works fine when I tested it on HAPS platform
(using Felipe's next branch).
BR,
Thinh
