Re: Serial device with very large buffer

From: Joe deBlaquiere (
Date: Thu Feb 01 2001 - 23:56:52 EST

Hi Alex!

        I'm a little confused here... why are we overrunning? This thing is
running externally at 19200 at best, even if it does all come in as a
packet. I would think the flip buffer would never contain more than a
few characters. Are you running it at a higher rate internally? Does it
buffer up a whole packet if you do this?

Wouldn't it be a little easier to drop somthing like "AT#MRU=500\r" to
the modem than to change the tty driver?


Alex Belits wrote:

> On Thu, 1 Feb 2001, Alan Cox wrote: > > >>> I also propose to increase the size of flip buffer to 640 bytes (so the >>> flipping won't occur every time in the middle of the full buffer), however >>> I understand that it's a rather drastic change for such a simple goal, and >>> not everyone will agree that it's worth the trouble: >> >> Going to a 1K flip buffer would make sense IMHO for high speed devices too > > > 1K flip buffer makes the tty_struct exceed 4096 bytes, and I don't think, > it's a good idea to change the allocation mechanism for it.

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