Messages in this thread |  | | Date | Sun, 14 Oct 2001 08:12:34 +0200 | From | Pavel Machek <> | Subject | Re: [ANNOUNCE] FUSD v1.00: Framework for User-Space Devices |
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Hi!
> > > > Yep. And linmodem driver does signal processing, so it is big and > > > > ugly. And up till now, it had to be in kernel. With your patches, such > > > > drivers could be userspace (where they belong!). Of course, it would be > > > > very good if your interface did not change... > > > > > > I don't see how linmodem drivers apply. At least not at the low-level > > > because you actually have to driver the hardware, respond to interrupts > > > etc. On some of this I can see a driver split like there is for the video > > > > You don't actually need interrupts -- you *know* when next sample arrives. > > And port io is completely fine with iopl() ;-). > > But DMA? You are talking about what amounts to a sound card driver. > And since in the cases that burn cpu time you have to process raw > sound samples into modem data, you need to shift a fair amount of > data. inb and outb just don't have the bandwidth. So you need a > kernel side component that drives the hardware to some extent.
You need to push 8kHz/16bit, that's 16 kilobytes per second. Or maybe you can sample at 11kHz, getting 20 kilobytes per second. Comfortably done with inb/outb.
> Additionally you still don't need a FUSD driver for that case. All > you need is to have is a ptty. Because that is what modem drivers > are now. And the ptty route has binary and source compatiblity > to multiple unix platforms.
I do not think tty/pty pair does cut it for AT emulation. Can you really emulate all neccessary features using pty/tty? Pavel -- Casualities in World Trade Center: 6453 dead inside the building, cryptography in U.S.A. and free speech in Czech Republic. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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