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From: (Eric W. Biederman)
To: "Pavel Machek" <>
Cc: "Pavel Machek" <>,
	"Jeremy Elson" <>,
Subject: Re: [ANNOUNCE] FUSD v1.00: Framework for User-Space Devices
Date: 13 Oct 2001 15:57:32 -0600	[thread overview]
Message-ID: <> (raw)
In-Reply-To: <> <> <> <> <>
In-Reply-To: <>

"Pavel Machek" <> writes:

> 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.

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.


  reply	other threads:[~2001-10-13 22:08 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2001-09-29  1:18 Jeremy Elson
2001-10-01 15:36 ` Jeremy Elson
2001-10-02 18:48   ` Pavel Machek
2001-10-02 22:37     ` Jeremy Elson
2001-10-02 22:44       ` Mike Fedyk
2001-10-05 18:51       ` Pavel Machek
2001-10-08  2:09         ` Eric W. Biederman
2001-10-08  2:37           ` linmodems (was Re: [ANNOUNCE] FUSD v1.00: Framework for User-Space Devices) Jeff Garzik
2001-10-08 12:19             ` Pavel Machek
2001-10-08 19:34             ` Tim Jansen
2001-10-08 12:20           ` [ANNOUNCE] FUSD v1.00: Framework for User-Space Devices Pavel Machek
2001-10-13 21:57             ` Eric W. Biederman [this message]
2001-10-14  6:12               ` Pavel Machek
2001-10-15 12:34                 ` Jamie Lokier
2001-10-15 12:38                 ` Jamie Lokier
2001-10-10  3:55         ` Jeremy Elson

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