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Hi, I have written a driver for a Wireless LAN chip for PXA270M arm platform. The wireless lan interface is eth1. I am able to ping the interface. I was ...
  1. 05-18-2011 #1
    sumitv
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    NETDEV WATCHDOG: eth1: transmit timed out error

    Hi,

    I have written a driver for a Wireless LAN chip for PXA270M arm platform. The wireless lan interface is eth1.

    I am able to ping the interface. I was performing stress testing on the eth1 interface. I kept pinging eth1 interface from the other PC in the same network overnight. After some time, I saw following error message on the debug console :

    NETDEV WATCHDOG: eth1: transmit timed out

    I went through some of the kernel code. As I understand, this error message comes if MAC layer (Wireless LAN Hardware) fails to transmit data packet over the air returning an error to kernel.

    Is this because of Hardware not in ready state or Mac layer hang? If yes, how can I resolve this?
    Will reseting Wireless LAN chip resolve this problem? I am working on this to debug further.

    For your information, I have ported linux kernel version 2.6.19 on my PXA270M arm unit.

    Regards,
    Sumit
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  2. 05-21-2011 #2
    Rubberman
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    Overnight testing, and only one error like this? Remember, ping is a UDP protocol, so packet loss is expected, which can be caused by any number of environmental or system load factors.
    Sometimes, real fast is almost as good as real time.
    Just remember, Semper Gumbi - always be flexible!
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  3. 05-22-2011 #3
    sumitv
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    No. There seems to be other errors as well related to interrupts in WLAN driver code. I am us'ing WPA supplicant but not able to make it work in adhoc mode.
    Hence using "iwconfig" to connect in adhoc mode. But iwconfig does not provide you reliable connection.

    Can it be the cause of making something in interrupt handling??
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  4. 05-22-2011 #4
    Rubberman
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    Quote Originally Posted by sumitv View Post
    No. There seems to be other errors as well related to interrupts in WLAN driver code. I am us'ing WPA supplicant but not able to make it work in adhoc mode.
    Hence using "iwconfig" to connect in adhoc mode. But iwconfig does not provide you reliable connection.

    Can it be the cause of making something in interrupt handling??
    Proper interrupt handling is often the bugaboo of device driver (and real-time) code. Have you closely inspected drivers for other wireless devices?
    Sometimes, real fast is almost as good as real time.
    Just remember, Semper Gumbi - always be flexible!
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