Hi Jean, > May I ask what shell (and version) you're using? Both sequences above > return 255 here. bash -version says: GNU bash, version 3.2.25(1)-release (i486-pc-linux-gnu) Copyright (C) 2005 Free Software Foundation, Inc. I have a fresh and totaly normal installed Ubuntu 7.10 32-bit without any modifications. My user account and its homedir is also new. The bad is that this is likely the most used distributation is the next year. > It would take a broken shell to do what you describe, if that's > possible at all. The following command should answer your question: > > echo 0 > /sys/class/hwmon/hwmon0/device/pwm1_enable ; echo 255 > /tmp/pwm1 ; cat /tmp/pwm1 > > Here, it prints the expected error message, then 255. -------------------------------------------------------------------------- root at alex:~# echo 0 > /sys/class/hwmon/hwmon0/device/pwm1_enable ; echo 255 > /tmp/pwm1 ; cat /tmp/pwm1 bash: echo: write error: Invalid argument 0 255 root at alex:~# cat /tmp/pwm1 0 255 -------------------------------------------------------------------------- As you can see it prints the error message, the 0 and the 255. And you can see both go into /temp/pwm1. -------------------------------------------------------------------------- root at alex:~# echo 0 > /sys/class/hwmon/hwmon0/device/pwm1_enable 2>/dev/null ; echo 255 > /tmp/pwm1 ; cat /tmp/pwm1 0 255 -------------------------------------------------------------------------- Here the error goes to /dev/null. -------------------------------------------------------------------------- root at alex:~# echo 0 > /sys/class/hwmon/hwmon0/device/pwm1_enable >/dev/null 2>/dev/null ; echo 255 > /tmp/pwm1 ; cat /tmp/pwm1 255 -------------------------------------------------------------------------- And so the 0. > I meant that the patch is functionally incorrect, not that I was not > able to apply it (although it is, indeed, technically incorrect, for > it's reverted and not in unified format.) Ok. Excuse me. This was a simple diff between the two files. I have no experiences in creating a real patch. > An additional > /dev/null can certainly hurt, as it overwrites the > previous > $ENABLE, meaning that you do NOT write the value to the > sysfs file at all. It doesn't make a difference for you because writing > 0 to pwm1_enable doesn't actually work with the w83627ehf driver, but > your change breaks drivers for which it works. Ok. Thats a good point. I thought that it redirects the hanging zero to /dev/null. But I see echo 0 is the command and > $ENABLE is the regirection of the stdout. But why does pwm1_enable not consume the 0 and throws the error afterwards? Regards Alex -------------- next part -------------- A non-text attachment was scrubbed... Name: not available Type: application/pgp-signature Size: 189 bytes Desc: This is a digitally signed message part Url : http://lists.lm-sensors.org/pipermail/lm-sensors/attachments/20071118/8bdfc0e5/attachment.bin
