Re: Official bugreport 4.1 kernel (audio gadget and ChipIdea)

[Marek Vasut <marex@denx.de>]

On Tuesday, June 30, 2015 at 04:23:01 AM, Peter Chen wrote:
> On Fri, Jun 26, 2015 at 07:15:18PM +0200, Sébastien Pruvost wrote:
> > Hello,
> > 
> > I'm sending this mail to report a bug concerning the latest kernel 4.1.
> > 
> > Here is the problem (and the test I've done):
> >                 I have firstly used the 3.10.53 kernel for my two
> >                 sabrelites in
> > 
> > order to use the audio gadget driver with the Dual Role ChipIdea
> > Controller (in order to switch roles between my two IMX6 sabreLite).
> > After loading g_audio in my two sabreLite and plugging the cable (microA
> > – microB), there is an error “ci_hdrc.0 request length too big for
> > isochronous snd_uac2.0 1116 Error”.
> > And even after running aplay command, I still got this error and there is
> > no sound getting out of the jack port.
> > I've switched roles between the two boards by following this: https://
> > www.kernel.org/doc/Documentation/usb/chipidea.txt.
> > This works fine with the serial driver, I can see a new serial interface
> > (host side) and after switching role a new serial interfaces at device
> > side. Same thing for ethernet gadget: this works fine too. But not with
> > the audio gadget. In fact, there is a new audio interface at host side
> > but I can not interact with it (even alsamixer doesn’t see any controls
> > on this new sound card). I’ve tested that audio gadget works fine if I
> > don’t use ChipIdea HighSpeed Dual Role Controller.
> > 
> >                 Secondly I have tested this audio gadget with the latest
> >                 Kernel
> > 
> > 4.1 for my two IMX6 sabrelites (imx_v6_v7_defconfig). Now these previous
> > errors are gone but there are still no sound getting out of the jack
> > port (even if there are a new sound card in host side)
> 
> It is may not a role switch problem, please check if the g_audio can
> work well with an ubuntu PC (make sure your codec works well).

ci_hdrc.0 request length too big for isochronous

Doesn't this just mean it cannot transfer such a long buffer via ISO pipe ?
I guess the UAC should send smaller buffers to work with the CI HDRC?

Best regards,
Marek Vasut