Re: overruns with kernel 2.4.19

[David Lawyer <dave@lafn.org>]

On Tue, Feb 18, 2003 at 02:43:46PM +0100, Joachim Buermann wrote:
> Hello all,
> 
> I`m using linux mandrake kernel 2.4.19 on a 2 GHz Pentium 4 with 128
> MByte RAM. The serial port /dev/cua0 is connected to a external device
> and receives data with 115200 Baud.
The cua devices have been obsolete for some time.
> 
> Unfortunately I get a lot of fifo overruns. I have unmasked the hda
> interrupts with:
> 
> hdparm -u1 /dev/hda
> 
> also set the low_latency flag in the serial driver. The harddisk dma
> couldn't disabled.
> 
> I'm wonder at this behavior, because with a lower machine (Pentium I
> 120 MHz, Kernel 2.2.13) I get overruns only once in a blue moon. And I
> expected, that a 2 GHz machine should be quick enough, to responds to
> the serial interrupts.

Almost the same for me.  On a Pentium I 90 MHz I get no overruns with
kernel 2.2.20, but get hundreds of overruns on the same machine with
kernel 2.4.19.  Something is wrong with the software.
> 
			David Lawyer