From: Alexander Gordeev Date: Thu, 13 Jan 2011 01:00:56 +0000 (-0800) Subject: ntp: add hardpps implementation X-Git-Tag: v2.6.38-rc1~284 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=025b40abe715d638e60516a657d354e8560c1a85;p=pandora-kernel.git ntp: add hardpps implementation This commit adds hardpps() implementation based upon the original one from the NTPv4 reference kernel code from David Mills. However, it is highly optimized towards very fast syncronization and maximum stickness to PPS signal. The typical error is less then a microsecond. To make it sync faster I had to throw away exponential phase filter so that the full phase offset is corrected immediately. Then I also had to throw away median phase filter because it gives a bigger error itself if used without exponential filter. Maybe we will find an appropriate filtering scheme in the future but it's not necessary if the signal quality is ok. Signed-off-by: Alexander Gordeev Acked-by: John Stultz Cc: Rodolfo Giometti Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- Reading git-diff-tree failed