Paul Fulghum <[email protected]> wrote:
> Try the following patch, and report the syslog output.
>
> This may be lost receive data due to full flip buffer.
> 2.6.9 would try processing rx data in the ISR if the
> flip buffer was full. This violated locking requirements
> and was changed to only process rx data in scheduled work.
> This can slow the processing of data.
I have tried your patch. The following is a part of syslog
output.
------------------------------------------------------------------
Feb 16 23:52:40 moka kernel: receive_chars:flip full:low_latency=0
Feb 16 23:52:40 moka kernel: receive_chars:flip full:discard char
------------------------------------------------------------------
I have got this pair of two lines many times while running the
wget command.
> Also try using the setserial utility to set
> the 'low_latency' option for the device. That should
> operate the same as 2.6.9 (which can be dangerous).
With 'low_latency' option in 2.6.15 with your patch, the problem
did not occur and no output from syslog.
> The improved flip buffering code in 2.6.16-rc3
> should also prevent any loss of data. If possible,
> try 2.6.16-rc3.
I have tried 2.6.16-rc3. With or without 'low_latency' option,
the problem did not occur. It seems to work fine! I will use
2.6.16-rc3 or later.
If you have any additional plan to pin down this problem, I will
try your patch.
Thank you for your help,
Kouji Toriatama
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