Subject: [linux-audio-dev] Re: [Alsa-devel] Fwd: Re: USB Quattro Linux support
From: James Tappin (sjt_AT_star.sr.bham.ac.uk)
Date: Mon Apr 15 2002 - 15:35:32 EEST
On Monday 15 Apr 2002 13:16, Patrick Shirkey wrote:
> --- Paul Davis <pbd_AT_op.net> wrote:
> >>>framework for ALSA worked out, which is even more of a problem. Its
> >>>still unclear at this point whether the ALSA framework will be:
> >>>
> >>>
> >>> application<->alsa-lib<->alsa-driver<->low-level-ALSA-USB-class-driver
> >>>
> >>>OR
> >>>
> >>> application<->alsa-lib<->low-level-non-ALSA-USB-class-driver
> >>>
> >>>the first one is easier to write, the second one is more flexible.
>
> I think a good example of how ALSA should work with USB devices is the
> gphoto approach. From what I know of their framework it is along the same
> lines as the first option.
I think a more exact description of the gphoto approach is:
application<->gphoto-lib<->usb-lib<->low-level-generic-USB driver.
Only the low-level kernel USB drivers and the usbdevfs filesystem are in
kernel space, beyond that the hardware driving is done via the user-space
libusb. I'm not sure whether this would have low-enough latency for audio
use, after all, digital cameras aren't timing-critical for the sort of things
that gphoto aims to do.
-- +------------------------+-------------------------------+---------+ | James Tappin | School of Physics & Astronomy | O__ | | sjt_AT_star.sr.bham.ac.uk | University of Birmingham | -- \/` | | Ph: 0121-414-6462. Fax: 0121-414-3722 | | +--------------------------------------------------------+---------+
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