On Wed, Sep 21, 2016 at 08:27:02AM -0500, Bin Liu wrote:
> On Wed, Sep 21, 2016 at 11:01:21AM +0300, Felipe Balbi wrote:
> >
> > Hi,
> >
> > Bin Liu <b-liu@xxxxxx> writes:
> > > Hi,
> > >
> > > I am trying to check Isoch high bandwidth transfer with g_webcam.ko in
> > > high-speed connection.
> > >
> > > First I hacked webcam.c as follows to enable 640x480@30fps mode.
> > >
> > > diff --git a/drivers/usb/gadget/legacy/webcam.c b/drivers/usb/gadget/legacy/webcam.c
> > > index 72c976b..9eb315f 100644
> > > --- a/drivers/usb/gadget/legacy/webcam.c
> > > +++ b/drivers/usb/gadget/legacy/webcam.c
> > > @@ -191,15 +191,15 @@ static const struct UVC_FRAME_UNCOMPRESSED(3) uvc_frame_yuv_360p = {
> > > .bFrameIndex = 1,
> > > .bmCapabilities = 0,
> > > .wWidth = cpu_to_le16(640),
> > > - .wHeight = cpu_to_le16(360),
> > > + .wHeight = cpu_to_le16(480),
> > > .dwMinBitRate = cpu_to_le32(18432000),
> > > .dwMaxBitRate = cpu_to_le32(55296000),
> > > - .dwMaxVideoFrameBufferSize = cpu_to_le32(460800),
> > > - .dwDefaultFrameInterval = cpu_to_le32(666666),
> > > + .dwMaxVideoFrameBufferSize = cpu_to_le32(614400),
> > > + .dwDefaultFrameInterval = cpu_to_le32(333333),
> > > .bFrameIntervalType = 3,
> > > - .dwFrameInterval[0] = cpu_to_le32(666666),
> > > - .dwFrameInterval[1] = cpu_to_le32(1000000),
> > > - .dwFrameInterval[2] = cpu_to_le32(5000000),
> > > + .dwFrameInterval[0] = cpu_to_le32(333333),
> > > + .dwFrameInterval[1] = cpu_to_le32(666666),
> > > + .dwFrameInterval[2] = cpu_to_le32(1000000),
> > > };
> > >
> > > then loaded g_webcam.ko as
> > >
> > > # modprobe g_webcam streaming_maxpacket=3072
> > >
> > > The endpoint descriptor showing on the host is
> > >
> > > Endpoint Descriptor:
> > > bLength 7
> > > bDescriptorType 5
> > > bEndpointAddress 0x8d EP 13 IN
> > > bmAttributes 5
> > > Transfer Type Isochronous
> > > Synch Type Asynchronous
> > > Usage Type Data
> > > wMaxPacketSize 0x1400 3x 1024 bytes
> > > bInterval 1
> > >
> > > However the usb bus trace shows only one transaction with 1024-bytes packet in
> > > every SOF. The host only sends one IN packet in every SOF, I am expecting 2~3
> > > 1024-bytes transactions, since this would be required to transfer 640x480@30fps
> > > YUV frames in high-speed.
> > >
> > > DId I miss anything in the setup?
> >
> > MUSB or DWC3? This looks like a UDC bug to me. Can you show a screenshot
>
> Happened on both MUSB and DWC3.
Indeed, it is MUSB gadget driver problem.
>
> > of your bus analyzer? When host sends IN token, are you replying with
>
> The trace screenshot on DWC3 is attached.
>
> > DATA0, DATA1 or DATA2?
>
> Good hint! It is DATA0!
>
> >
> > --
> > balbi
>
> Regards,
> -Bin.
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