am335x g_audio gadget issue

Andrea Cattani

Hi all,

On my AM335X evaluation board I'm trying to use g_audio gadget in order to export the internal audio codec to
the host PC. The insmod operation is ok, but when the USB link is detected I got a lot of "gadget: ep1out queue req: -108" errors. The audio codec is detected but not usable from the PC host:

root@am335x-evm:~#
root@am335x-evm:~# modprobe g_audio
[ 540.661682] gadget: Hardware params: access 3, format 2, channels 2, rate 48000
[ 540.669647] gadget: audio_buf_size 48000, req_buf_size 200, req_count 256
[ 540.676818] gadget: Linux USB Audio Gadget, version: Dec 18, 2008
[ 540.683319] gadget: g_audio ready
[ 540.686920] musb-hdrc musb-hdrc.0: MUSB HDRC host driver
[ 540.692535] musb-hdrc musb-hdrc.0: new USB bus registered, assigned bus number 2
[ 540.700378] usb usb2: New USB device found, idVendor=1d6b, idProduct=0002
[ 540.707489] usb usb2: New USB device strings: Mfr=3, Product=2, SerialNumber=1
[ 540.714996] usb usb2: Product: MUSB HDRC host driver
[ 540.720184] usb usb2: Manufacturer: Linux 3.2.0 musb-hcd
[ 540.725738] usb usb2: SerialNumber: musb-hdrc.0
[ 540.731079] hub 2-0:1.0: USB hub found
[ 540.735015] hub 2-0:1.0: 1 port detected
root@am335x-evm:~#
root@am335x-evm:~# [ 550.798522] gadget: high-speed config #1: Linux USB Audio Gadget
[ 550.805725] gadget: ep1out queue req: -108
[ 550.961212] gadget: ep1out queue req: -108
[ 550.965850] gadget: ep1out queue req: -108
[ 550.970520] gadget: ep1out queue req: -108
[ 550.975524] gadget: ep1out queue req: -108
[ 550.980529] gadget: ep1out queue req: -108
[ 550.985717] gadget: ep1out queue req: -108
[ 550.990386] gadget: ep1out queue req: -108
......
......

I'm using latest SDK (6.0.0.0).
Any suggestions?

Many thanks,
Andrea

over 12 years ago

0 Bin Liu over 12 years ago

TI__Guru**** 168421 points

Andrea,

g_audio gadget is not validated and supported on AM335x Linux SDK.

In a quick look of this '-108' error, I can tell in Line 577 in drivers/usb/gadget/f_audio.c when calling usb_ep_enable(out_ep), out_ep->desc is empty, which causes the error.

But assigning ->desc to a proper data location does not make g_audio fully working - then I faced kernel OOPS due to g_audio does not tear down out_ep properly when playing with unplugging/plugging the USB cable and rmmod/insmod g_audio.ko.

0 Andrea Cattani over 12 years ago in reply to Bin Liu

Intellectual 380 points

Bin,

I'm trying to investigate more deeply this issue.
Could you please suggest me how to assigning ->desc to a proper data location?

Regards,
Andrea

0 Bin Liu over 12 years ago in reply to Andrea Cattani

TI__Guru**** 168421 points

Please try this:

diff --git a/drivers/usb/gadget/f_audio.c b/drivers/usb/gadget/f_audio.c
index ec7ffcd..871b0e6 100644
--- a/drivers/usb/gadget/f_audio.c
+++ b/drivers/usb/gadget/f_audio.c
@@ -574,6 +574,7 @@ static int f_audio_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
 
        if (intf == 1) {
                if (alt == 1) {
+                       out_ep->desc = &as_out_ep_desc;
                        usb_ep_enable(out_ep);
                        out_ep->driver_data = audio;
                        audio->copy_buf = f_audio_buffer_alloc(audio_buf_size);

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am335x g_audio gadget issue