Re: cdns3 uvc first ISO parkage lost problem

[Frank Li]

On Mon, Nov 06, 2023 at 11:12:10AM +0000, Pawel Laszczak wrote:
> >
> >On Mon, Oct 30, 2023 at 06:34:48AM +0000, Pawel Laszczak wrote:
> >>
> >> >
> >> >hi Pawel Laszczak
> >> >
> >> >Recently, I met the problem when use uvc. UVC report jpg header error.
> >> >
> >> >Basic reproduce steps.
> >> >Gadget side:
> >> >1 -
> >> >	https://urldefense.com/v3/__https://gist.github.com/kbingham/c39c
> >>
> >>4cc7c20882a104c08df5206e2f9f?permalink_comment_id=3270713__;!!EHsc
> >m
> >>
> >>S1ygiU1lA!H1h8GlLnbS6vqklXm_2qGyinP638O62Kk2eLB9zeMkjAGXUAPYyPXD
> >L
> >> >FasSqYt16xq0RGT0Ff-cP4A$
> >> >	uvc-gadget.sh start
> >> >2 -
> >> >	https://urldefense.com/v3/__https://git.ideasonboard.org/uvc-
> >>
> >>gadget.git__;!!EHscmS1ygiU1lA!H1h8GlLnbS6vqklXm_2qGyinP638O62Kk2eLB
> >9z
> >> >eMkjAGXUAPYyPXDLFasSqYt16xq0RGT1ogOdRQA$
> >> >	uvc-gadget -i test.jpg
> >> >
> >> >
> >> >Host side:
> >> >	https://urldefense.com/v3/__https://github.com/thekvs/uvccapture2
> >>
> >>__;!!EHscmS1ygiU1lA!H1h8GlLnbS6vqklXm_2qGyinP638O62Kk2eLB9zeMkjAG
> >X
> >> >UAPYyPXDLFasSqYt16xq0RGT1MNlKiXA$
> >> >	uvccapture2 --device /dev/video0  --resolution 640x360 --count 1 --
> >> >result 8qxp.jpeg
> >> >
> >> >	It will report jpeg header error.
> >> >
> >> >
> >> >After debugs, I found two problem.
> >> >
> >> >Problem 1, sg is enabled. so uvc driver will use sg. each package
> >> >include two trb,  trb0 is 8bytes header, trb1 is 1016bytes. total 1024.
> >> >
> >> >num_trb here is wrong.
> >> >it should be
> >> >	num_trb = priv_ep->interval * request->num_mapped_sgs.
> >> >
> >> >because priv_ep->interval is 1, I just simple set to
> >> >request->num_mapped_sg as below patch. USB analyer show one whole
> >> >1024 ISO package sent out as expectation although document said only
> >> >support one TD when use ISO (Maybe my doc is too old).
> >>
> >> Support for sg  in uvc has been added after upstreaming this driver,
> >> so the driver needs some improvement.
> >>
> >> Calculating of num_trb probably will more complicated change.
> >>
> >> You can see how it is implemented in
> >>
> >https://urldefense.com/v3/__https://elixir.bootlin.com/linux/latest/source/d
> >rivers/usb/gadget/udc/cdns2/cdns2-
> >gadget.c*L412__;Iw!!EHscmS1ygiU1lA!EZS2StTKnSzdCT7N5B1-
> >l8nGXQgS63KwgcGINcpBC8rnRJu2u8ryV1UjwQb6YfwYLPq9T_115KC5qQ$ .
> >>
> >> CDNS2 is different controller and support only HS but has borrowed the
> >DMA part from CDNS3.
> >> It was upsteamed after adding sg to UVC.
> >>
> >> Regarding TD, it is true that controller can support only one TD per
> >> SOF but this TD can contain many TRBs
> >
> >Okay, great. I can work a patch if I can resolve problem 2.
> 
> At this moment I don't know how to resolve the problem 2.
> I'm going to recreate this case on my side and try to find some solution.
> 
> Pawel 

I post a sg ISO fix patch, in case you need it.
https://lore.kernel.org/imx/BYAPR07MB538112FE4150BC19696D7613DDAAA@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx/#R

It fixed my case. but android looks like still issue. Recently quite busy.

Frank Li

> 
> >
> >>
> >> >
> >> >diff --git a/drivers/usb/cdns3/cdns3-gadget.c
> >> >b/drivers/usb/cdns3/cdns3- gadget.c index
> >> >69a44bd7e5d02..8cc99a885883f 100644
> >> >--- a/drivers/usb/cdns3/cdns3-gadget.c
> >> >+++ b/drivers/usb/cdns3/cdns3-gadget.c
> >> >@@ -1125,10 +1125,7 @@ static int cdns3_ep_run_transfer(struct
> >> >cdns3_endpoint *priv_ep,
> >> >        struct scatterlist *s = NULL;
> >> >        bool sg_supported = !!(request->num_mapped_sgs);
> >> >
> >> >-       if (priv_ep->type == USB_ENDPOINT_XFER_ISOC)
> >> >-               num_trb = priv_ep->interval;
> >> >-       else
> >> >-               num_trb = sg_supported ? request->num_mapped_sgs : 1;
> >> >+       num_trb = sg_supported ? request->num_mapped_sgs : 1;
> >> >
> >> >        if (num_trb > priv_ep->free_trbs) {
> >> >                priv_ep->flags |= EP_RING_FULL;
> >> >
> >> >
> >> >*** Problem 2 ***
> >> >
> >> >According to doc and my observation, looks like hardware fetch data
> >> >into FIFO when get SOF, then transfer data when get IN token. Each
> >> >SOF will increase TRB regardless it is ready or not.
> >>
> >> Yes, but this fetched data will be sent in next  ITP.
> >>
> >> >
> >> >When gadget complete equeue ISO data, so SOF will increase TRB
> >> >regardless if there are IN token.
> >> >
> >> >   SOF       SOF       SOF     SOF  IN    SOF ....
> >> >      TRB0      TRB1      TRB2      TRB3  ...
> >> >
> >> >
> >> >Host may start get data at some time after gadget queue data.
> >> >
> >> >So TRB0..2 data will be lost.
> >> >
> >> >If it is audio data, it should be okay. But for uvc, it is jpeg
> >> >header, so host side report error.
> >> >
> >> >I checked dwc gadget driver, which start equeue ISO data only get NYET.
> >> >
> >> >I check cdns spec, there are ISOERR. But it is never happen.
> >> >According to document, ISOERR should issue when IN token and FIFO no
> >data.
> >> >
> >>
> >> Current CDNS3 driver has disabled ISOERR. Did you enable it?
> >
> >Yes, I enabled all IRQ.
> >
> >+       if (priv_ep->type == USB_ENDPOINT_XFER_ISOC && priv_ep->dir) {
> >+               priv_ep->flags |= EP_QUIRK_ISO_IN_NOST;
> >+               reg |= 0xFFFF;
> >+       }
> >
> >Supposed ISOERR should happen even DMA is disabled.
> >But I also tried enable DMA, and using lenght 0 TRB and link to loop.
> >
> >Still no ISOERR happen. I can see TRBADDR changed, but still no ISOERR
> >
> >
> > irq/447-5b13000-200     [000] d..1.    78.662729: cdns3_epx_irq: IRQ for ep2in:
> >00000804 IOC , ep_traddr: c0086018 ep_last_sid: 00000000 use_streams: 0
> >
> >	 ^^^^^^^
> > irq/447-5b13000-200     [000] d..1.    78.662851: cdns3_epx_irq: IRQ for ep2in:
> >00000804 IOC , ep_traddr: c008600c ep_last_sid: 00000000 use_streams: 0
> > irq/447-5b13000-200     [000] d..1.    78.662975: cdns3_epx_irq: IRQ for ep2in:
> >00000804 IOC , ep_traddr: c0086018 ep_last_sid: 00000000 use_streams: 0
> >
> >STS is 0x804, only IOC set.
> >
> >Frank
> >
> >>
> >> >I tried below method
> >> >	1.  Delay queue TRB, but no ISOERR.
> >> >	2.  queue a lenght 0 TRB,but no ISOERR
> >> >
> >> >My question is how to delay queue TRB to ISO IN token really happen
> >> >to avoid lost JPEG header.
> >> >
> >> >Frank
> >> >
> >> >
> >> >
> >> >
> >> >
> >>