On Sun, May 06, 2007 at 02:19:59PM +0200, Bodo Eggert wrote:
> Since you ask for random thoughts:
>
> IO of data streams from or to a DAC/ADC is essentially what soundcards do.
> I'm wondering if these cards are similar enough to use alsa, and if using
> that interface would ease or hinder programming the driver.
I had a short look at ALSA and it looks like it is a little bit too
focussed towards "normal" audio. For example, if follows an asynchronous
model in the sense that an application can read/write to a buffer at any
time, taken that the ringbuffer doesn't overflow. That's not enough for
example for control applications; you need the option for real
synchronous operation there.
IMHO we need an API which offers
- kernel ring buffers (to make it sure no data gets lost)
- generic data types (streaming plain ADC values is just the simplest
case; we also have for example streaming FPGA data containing
preprocessed data sets)
- optional timestamping for each sample
- zero-copy from hardware into userspace memory, with DMA support
- application notification every N samples (N >= 1)
v4l2 may also be worth a look; but in the end I suppose they are all
specialized sub-cases of what we'd need for fast DAQ.
Robert
--
Dipl.-Ing. Robert Schwebel | http://www.pengutronix.de
Pengutronix - Linux Solutions for Science and Industry
Handelsregister: Amtsgericht Hildesheim, HRA 2686
Hannoversche Str. 2, 31134 Hildesheim, Germany
Phone: +49-5121-206917-0 | Fax: +49-5121-206917-9
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to [email protected]
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/
[Index of Archives]
[Kernel Newbies]
[Netfilter]
[Bugtraq]
[Photo]
[Stuff]
[Gimp]
[Yosemite News]
[MIPS Linux]
[ARM Linux]
[Linux Security]
[Linux RAID]
[Video 4 Linux]
[Linux for the blind]
[Linux Resources]
