From: Henrik Rydberg <rydberg@euromail.se>
Date: Sun, 19 Oct 2008 03:27:43 +0000 (-0700)
Subject: hwmon: applesmc: lighter wait mechanism, drastic improvement
X-Git-Tag: v2.6.28-rc1~175
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=8c9398d1e9766e3659e277acb2e8ca1c17684139;p=pandora-kernel.git

hwmon: applesmc: lighter wait mechanism, drastic improvement

The read fail ratio is sensitive to the delay between the first byte
written and the first byte read; apparently the sensors cannot be rushed.
Increasing the minimum wait time, without changing the total wait time,
improves the fail ratio from a 8% chance that any of the sensors fails in
one read, down to 0.4%, on a Macbook Air.  On a Macbook Pro 3,1, the
effect is even more apparent.  By reducing the number of status polls, the
ratio is further improved to below 0.1%.  Finally, increasing the total
wait time brings the fail ratio down to virtually zero.

Signed-off-by: Henrik Rydberg <rydberg@euromail.se>
Tested-by: Bob McElrath <bob@mcelrath.org>
Cc: Nicolas Boichat <nicolas@boichat.ch>
Cc: "Mark M. Hoffman" <mhoffman@lightlink.com>
Cc: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
---

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