Damien Zammit wrote:
> S/PDIF mode works by setting the required flag
> in usbaudio.c. I think the device can't do both simultaneously,
> since different altsettings are required to set it.
Does the Windows driver allow it?
> Remaining issues:
> 1) Double check endianess of 24 bit capture.
This should be apparent even in low-amplitude noise.
Do you have a hex dump of recorded data?
> @@ -2441,6 +2441,12 @@ static int parse_audio_format_i_type(struct snd_usb_audio *chip, struct audiofor
> fp->altsetting, sample_width, sample_bytes);
> break;
> }
> +
> + /* Digidesign Mbox 2 workaround:
> + * supports S24_3BE BIG ENDIAN */
> + if (chip->usb_id == USB_ID(0x0dba, 0x3000))
> + pcm_format = SNDRV_PCM_FORMAT_S24_3BE;
Please put this into is_big_endian_format().
> + /* Digidesign Mbox 2: skip altsets incompatible with device_setup
> + */
But there isn't actually a device_setup parameter?
> +mbox2_reboot:
> + snd_usb_ctl_msg(dev, usb_rcvctrlpipe(dev, 0),
> + 0x85, 0xc0, 0x0001, 0x0000, &bootresponse, 0x0012, 1000);
> +
> + if (bootresponse == MBOX2_BOOT_LOADING) {
> + snd_printdd("device not ready, resending boot sequence...\n");
> + goto mbox2_reboot;
> + }
This could be made a loop. And it could run infinitely long; maybe you
should add a timeout. (How long does it usually need?)
> + err = usb_get_descriptor(dev, USB_DT_DEVICE, 0,
> + &dev->descriptor, sizeof(dev->descriptor));
> + config = dev->actconfig;
> + if (err < 0) snd_printdd("error usb_get_descriptor: %d\n", err);
> + err = usb_reset_configuration(dev);
Does this device change its descriptors without a reset?
> + * 80 bb 00 = 24bit mode - S24_3BE
> + * 44 ac 00 = 16bit mode?
0xbb80 = 48000
0xac44 = 44100
Do the descriptors change if you change the sample rate? Or does using
44.1 kHz result in another altsetting?
> + snd_printdd("unknown bootresponse, ignoring device: %d\n",bootresponse);
> + return -ENODEV;
> + }
> + snd_printdd("Invalid firmware size: %d\n",fwsize);
> + return -ENODEV;
snd_printdd is for debugging output, but a failure due to a new firmware
revision should be indicated in any case.
> +#ifdef MBOX2_SPDIF_IO
This should be done at runtime. This would need logic to prevent using
analog/digital at the same time(?), and it might be necessary to
hardcode interfaces and if numbers in find_format().
> + * We have to make sure that the USB core looks
> + * again at interface 6
Why?
Best regards,
Clemens
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