usb audio class device itself should be your capture device. i guess you should be opening same audio usb device at time of snd_pcm_open ________________________________________ From: Rajul Kumar [rajul.manit1@gmail.com] Sent: Friday, November 12, 2010 3:40 PM To: Irfan Shaikh Cc: Clemens Ladisch; tiwai@suse.de; alsa-devel@alsa-project.org Subject: Re: [alsa-devel] ALSA error : frame 0 active: -75
Hi ,
Thanx for your reply .
We are simply using audio class driver and linux usb host stack . Can u let me know more regarding which capture buffer size to increase we are doing usb audio streaming on usb host side .
Thanx & Regards Rajul
On Fri, Nov 12, 2010 at 3:30 PM, Irfan Shaikh irfan.shaikh@sasken.com wrote:
Increase the size of your Capture Buffer in capture device (USB audio class) I guess this would help you in solving the Overrun problem ________________________________________ From: alsa-devel-bounces@alsa-project.org [alsa-devel-bounces@alsa-project.org] On Behalf Of Rajul Kumar [rajul.manit1@gmail.com] Sent: Friday, November 12, 2010 2:32 PM To: Clemens Ladisch Cc: tiwai@suse.de; alsa-devel@alsa-project.org Subject: Re: [alsa-devel] ALSA error : frame 0 active: -75
Hi ,
Thanx for the reply . i have a few more queries . please find time to guide regarding these .
is it possible to have some software solution from audio class driver for -EOVERFLOW condition ?
As depicted from error-codes.txt , -EOVERFLOW can be indicative of hardware problem also .
Can we be suggested how we can make sure that problem lies in the hardware only ( i mean via some code in usb stack or anything else ) .
Are there some mandatory H/W requirements for iso transfer usb signal which may not be required for bulk or other transfers , without which iso transfers can report H/W errors anytime ?
how can usb signal be improved so as to perfectly support iso transfers ?
Thanx & Regards Rajul
On Fri, Nov 12, 2010 at 2:16 PM, Clemens Ladisch clemens@ladisch.de wrote:
Rajul Kumar wrote:
ALSA sound/usb/usbaudio.c:354: frame 0 active: -75
-75 = -EOVERFLOW
which is followed by coninous loop of below messages :
ALSA sound/usb/usbaudio.c:354: frame 0 active: -71
-71 = -EPROTO
ALSA sound/usb/usbaudio.c:354: frame 0 active: -18
-18 = -EXDEV
Documentation/usb/error-codes.txt says: | -EOVERFLOW (*) The amount of data returned by the endpoint was | greater than either the max packet size of the | endpoint or the remaining buffer size. "Babble".
| -EPROTO (*, **) a) bitstuff error | b) no response packet received within the | prescribed bus turn-around time | c) unknown USB error
| -EXDEV ISO transfer only partially completed | look at individual frame status for details
| (*) Error codes like -EPROTO, -EILSEQ and -EOVERFLOW normally indicate | hardware problems such as bad devices (including firmware) or cables.
Regards, Clemens
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