T60 serial parallel port bay adapter, serial problem

[kccheng]

I am connecting to my device's serial port console, running at 115200 8n1 no flow control. all my computer can run this speed with no problem at all. but this bay adapter serial port is dropping bytes quite seriously, I have checked IRQ setting, device manager com port, turn FIFO usage level to the lowest, the situation do not get well a lot.
i thought it's windows ACPI's interrupt latency, but a pcmcia to serial adapter card work perfectly in my T60.

I remember setting something like this in windows 2000 + ACPI mode, in that case all PCI device would use the same IRQ, causing latency. I had to turn off ACPI by hard updating the computer driver from ACPI computer to Standard PC, and then PCI device would use different IRQs.

it's clean installed windows xp pro, with all lenovo recommended patches, and a suspend/resume patch
com1 is 3F8 irq4 if anybody is interested... I'm almost going back to DOS age.
anybody use this bay adapter too?

[RonS]

Have you tried adding the /NOSERIALMICE to the BOOT.INI startup switches?

[kccheng]

added as u suggested, no luck yet.

[RonS]

I don't have the Serial/Parallel bay adapter, but I have an Advanced Dock with a serial port. On my T60, Int4 is assigned to COM1 (0x3F8) without making any changes re ACPI. Nothing else appears to share Int4.

Here are a few random thoughts:

1. Have you tried your test running in Safe Mode? If you don't get errors in Safe Mode, then perhaps there's a service or background task that's taking CPU resources.

2. You should set the FIFO usage to the middle, so you get a balance of fewer interrupts and deep enough input queue to prevent buffer overruns in the 16550.

3. It would be interesting to see if the data loss is occuring at the device, device driver, or application level. Try using the Task Manager to set your Process's priority level to High or Realtime.

4. In System->Advanced->Performance Settings->Advanced, try changing the processor scheduling between Programs and Background services to see if that makes a difference.

5. I would go into the BIOS and disable the Infrared port just to make there there are no conflicts there.

[kccheng]

thanks for your suggestions, but unfortunately it is still dropping bytes.
i am planing to backup my system , then restore the computer to factory default install.