Re: TTY_FLIPBUF_SIZE too low causing dataloss on too fast serial lines?

Pavel Machek (pavel@bug.ucw.cz)
Thu, 27 May 1999 00:15:03 +0200


Hi!

> All at interrupt time. I wonder how do you solve this problem with
> serial ports: these days serials can be easily driven at speeds close
> to 1Mbit... (I'm talking about dumb on-board serials like NS PC87108).
>
> I simply haven't see much demand or practical application for high-speed
> serial transfers. It's restricted to short distance unless you use

Well, if you have two notebooks on the table, both 1Mbit capable, it
is kind of bad when you are not able to transfer at full speed. (Yes,
this happened to me. We actually had 10mbit coax cards, but cable was
broken and it was _really_ dodgy "yes, now it pings, please hold cable
like this before transfer finishes").

> The only reason why high-speed serial might be interesting is for those
> IR ports that look like serial ports, and there aren't that many

On short cable, for notebook-to-notebook data transfer, it seems very
practical to me. [serial cables are much more common than 10mbit
pcmcia cards.]

> interesting applications requiring that yet. I do intend to fix this; I
> just haven't seen a huge urgency to it. If someone has an actual,

Is there some easy way for me to make it work 'just now'? Like calling
tty_flip_buffer_push from some kind of bh or increasing hz to 1000 or
...? Why is size of struct tty limited to PAGE_SIZE in the first
place?
Pavel

-- 
I'm really pavel@ucw.cz. Look at http://195.113.31.123/~pavel.  Pavel
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