Re: Serial port blues

2007-01-22 Thread Alan
Serial port latency is heavily dependant on the HZ rate for data bits and input side stuff and you can set the low latency flag to improve upon that. Beyond that if you are using the modem control ioctls then it depends a lot on the hardware. USB has some implicit queuing on the bus but generic ua

Re: Serial port blues

2007-01-21 Thread H. Peter Anvin
H. Peter Anvin wrote: So write a kernel driver. It's not like we're locking anybody out. There is certainly enough Amateur Radio/Linux crossover that a kernel enhancement to support Amateur Radio is going to get frowned upon. Argh! Not only did the message go out twice, but that should h

Re: Serial port blues

2007-01-21 Thread Theodore Tso
On Sun, Jan 21, 2007 at 08:05:52PM +0100, Grzegorz Jaśkiewicz wrote: > > But on the other hand, PC nowadays are capable of handling RT tasks + > running multiple programs in background, but OS has to be build from ground > up to handle such conditions (I guess most RTOSes are justa about that, but

Re: Serial port blues

2007-01-21 Thread Theodore Tso
On Sun, Jan 21, 2007 at 08:05:57AM +0100, Willy Tarreau wrote: > Hmmm the busy loop is dirty as hell, even on SMP, but it works ;-) > I remember is was possible to reprogram the RTC to interrupt at 8192 Hz. > If the task is running with real time prio, it should get this accuracy, > or am I mistake

Re: Serial port blues

2007-01-21 Thread Theodore Tso
On Sun, Jan 21, 2007 at 04:10:58PM +0100, Grzegorz Jaśkiewicz wrote: > you're right, I used wrong term to describe. > But the problem still exists. Nowadays it should be possible to run many > serial ports fully accurate "at the same time". It is also true that the > same problem exists in windows,

Re: Serial port blues

2007-01-21 Thread Willy Tarreau
On Sun, Jan 21, 2007 at 03:50:32PM +0100, Grzegorz Ja?kiewicz wrote: > funny, how even very fast box can be useless for such activities with modern > kernels, such as linux. After all, serial ports don't require too much > horsepower to be highly accurate. > >From designer perspective, I would rath

Re: Serial port blues

2007-01-21 Thread Johannes Stezenbach
On Sun, Jan 21, 2007 at 08:05:57AM +0100, Willy Tarreau wrote: > On Sun, Jan 21, 2007 at 12:54:56AM -0500, Theodore Tso wrote: > > On Sat, Jan 20, 2007 at 06:36:44PM +0100, Willy Tarreau wrote: > > > > > Now he must be careful about avoiding busy loops in the rest of the > > > program, or he will

Re: Serial port blues

2007-01-20 Thread H. Peter Anvin
Joe Barr wrote: I'm forwarding this post by the author of a great little program for digital amateur radio on Linux, because I'm curious whether or not the problem he is seeing can be resolved outside the kernel. All comments welcome on/off list. Thanks, Joe Barr K1GPL [...] I've spent the

Re: Serial port blues

2007-01-20 Thread H. Peter Anvin
Joe Barr wrote: I'm forwarding this post by the author of a great little program for digital amateur radio on Linux, because I'm curious whether or not the problem he is seeing can be resolved outside the kernel. All comments welcome on/off list. Thanks, Joe Barr K1GPL [...] I've spent the

Re: Serial port blues

2007-01-20 Thread Willy Tarreau
On Sun, Jan 21, 2007 at 12:54:56AM -0500, Theodore Tso wrote: > On Sat, Jan 20, 2007 at 06:36:44PM +0100, Willy Tarreau wrote: > > On Fri, Jan 19, 2007 at 03:37:34PM -0600, Joe Barr wrote: > > > > > > I'm forwarding this post by the author of a great little program for > > > digital amateur radio

Re: Serial port blues

2007-01-20 Thread Theodore Tso
On Sat, Jan 20, 2007 at 06:36:44PM +0100, Willy Tarreau wrote: > On Fri, Jan 19, 2007 at 03:37:34PM -0600, Joe Barr wrote: > > > > I'm forwarding this post by the author of a great little program for > > digital amateur radio on Linux, because I'm curious whether or not the > > problem he is seein

RE: Serial port blues

2007-01-20 Thread Stuart MacDonald
From: On Behalf Of Joe Barr > I'm forwarding this post by the author of a great little program for > digital amateur radio on Linux, because I'm curious whether or not the > problem he is seeing can be resolved outside the kernel. From: w1hkj [mailto:[EMAIL PROTECTED] > I am now convinced that th

Re: Serial port blues

2007-01-20 Thread Willy Tarreau
Hi, On Fri, Jan 19, 2007 at 03:37:34PM -0600, Joe Barr wrote: > > I'm forwarding this post by the author of a great little program for > digital amateur radio on Linux, because I'm curious whether or not the > problem he is seeing can be resolved outside the kernel. At least, I see one wrong cla

Serial port blues

2007-01-20 Thread Joe Barr
I'm forwarding this post by the author of a great little program for digital amateur radio on Linux, because I'm curious whether or not the problem he is seeing can be resolved outside the kernel. All comments welcome on/off list. Thanks, Joe Barr K1GPL -- It's a strange world when proprieta