[Bug 260868] possible i386 regression after ce35a3bc852d25cb989bc1f3dc4ddb723d7d5117
Date: Mon, 03 Jan 2022 18:02:26 UTC
https://bugs.freebsd.org/bugzilla/show_bug.cgi?id=260868 --- Comment #13 from commit-hook@FreeBSD.org --- A commit in branch main references this bug: URL: https://cgit.FreeBSD.org/src/commit/?id=0e494a9e3fd86ef54899dcbe0268866629096c1e commit 0e494a9e3fd86ef54899dcbe0268866629096c1e Author: Mark Johnston <markj@FreeBSD.org> AuthorDate: 2022-01-03 15:14:41 +0000 Commit: Mark Johnston <markj@FreeBSD.org> CommitDate: 2022-01-03 18:00:50 +0000 x86: Skip late calibration if our reference timer has low quality Some AMD Geode-based systems end up using the 8254 PIT to calibrate the TSC during late calibration, which doesn't work because that timecounter's mask (65535) is much smaller than its frequency (1193182). Moreover, early calibration is done against the 8254 timer anyway. Work around the problem by simply using early calibration results if no high-quality timecounters exist. PR: 260868 Fixes: 22875f88799e ("x86: Implement deferred TSC calibration") Reported and tested by: mike@sentex.net, Stefan Hegnauer <stefan.hegnauer@gmx.ch> Reviewed by: imp, kib MFC after: 3 days Sponsored by: The FreeBSD Foundation Differential Revision: https://reviews.freebsd.org/D33730 sys/x86/x86/tsc.c | 7 +++++++ 1 file changed, 7 insertions(+) -- You are receiving this mail because: You are the assignee for the bug.