Lost characters on serial console

Lost characters on serial console

[Detlef Schmicker]

Hello,

we loose characters on the serial consol during receiving at 115kbaud. 
Especially if
the ide harddisk is used during reception.

We use a 300MHz Goede MediaGX, with a 16550A serial port (16 byte FIFO). We
tuned the Harddisk with hdparm, which reduced the problem, but it still 
exists.

We tried several Kernels: 2.4.4, 2.4.20, 2.4.24 and 2.6.0 and several 
patches "preempt" and "low-lattency".
No changes at all.
We used ext2 and ReiserFS file system.

There were some messages on this problem in the mailing list, but they 
are years old and we did not find
real hints, how to solve.

Can anybody help, can we help with debugging, testing?

Thanks a lot
Detlef Schmicker

Re: Lost characters on serial console

[Srihari Vijayaraghavan]

Hello Detlef,

I had similar issues (I cannot remember the exact error messages, but it was ppp which complained about the compression/decompression errors).

I do not see those error messages when I use USB to Serial converter (it uses pl2303 driver) under heavy hard drive (IDE in my case) load. I guess USB sub-system is not as interrupts sensitive as Serial ports.

Thanks
Hari