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  1. #1
    Just Joined!
    Join Date
    Nov 2010
    Allen, TX

    Serial Port CRC Errors - Idle Mode Dependent

    I need some help concerning power management in a Ubuntu system.

    I have two systems and am attempting to transmit a file using the serial port. The system receiving the file is running Ubuntu 10.04. I cannot send the file due to continuous CRC errors. It appears that bytes are being dropped due to the slow response time of the system coming out of power state C4.

    I have changed the idle boot parameter with the follwing results:

    idle=mwait: CRC errors
    idle=nomwait: CRC errors
    idle=halt: NO CRC errors
    idle=poll: NO CRC errors

    Any ideas why the serial port transfer cannot complete when I enter power state C4? Any settings I can change? Seems to work fine otherwise.

    Thanks in advance.

  2. #2
    Linux Guru Rubberman's Avatar
    Join Date
    Apr 2009
    I can be found either 40 miles west of Chicago, in Chicago, or in a galaxy far, far away.
    Laptops have a tendency to use the keyboard as the trigger for power-saving functionality. Even if the serial port is active, the system may go into a power-save mode because you have not diddled with the keyboard in some time. I can only recommend that you disable power-saving functionality altogether when you want to transfer data from one system to the other. If both systems are on A/C power, then you might be able to only adjust the power-save functions for operation under A/C power and leave the battery powered settings alone, but since you did not say what may be the case here, I don't know if that is an option for you or not.
    Sometimes, real fast is almost as good as real time.
    Just remember, Semper Gumbi - always be flexible!

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