From: sylvain.bertrand@gmail.com
To: bugzilla-daemon@freedesktop.org
Cc: dri-devel@lists.freedesktop.org
Subject: Re: [Bug 107784] [AMD tahiti XT] displayport broken
Date: Sun, 9 Sep 2018 03:45:49 +0000 [thread overview]
Message-ID: <20180909034549.GA451@freedom> (raw)
In-Reply-To: <bug-107784-502-s985ubzvG2@http.bugs.freedesktop.org/>
Found the bug, very probably.
It seems to be an upstream bug: a 32bits multiplication overflow on TSC
frequency introduced in recent TSC cleanup:
--------------------------------------------------------------------------------
commit cf7a63ef4e0203f6f33284c69e8188d91422de83
Author: Pavel Tatashin <pasha.tatashin@oracle.com>
Date: Thu Jul 19 16:55:38 2018 -0400
x86/tsc: Calibrate tsc only once
During boot tsc is calibrated twice: once in tsc_early_delay_calibrate(),
and the second time in tsc_init().
Rename tsc_early_delay_calibrate() to tsc_early_init(), and rework it so
the calibration is done only early, and make tsc_init() to use the values
already determined in tsc_early_init().
Sometimes it is not possible to determine tsc early, as the subsystem that
is required is not yet initialized, in such case try again later in
tsc_init().
--------------------------------------------------------------------------------
One nasty thing: this commit is broken, it does not compile, hence it's a
bisect "skipped" commit.
Roughly, if you have a cpu with a frequency above 4.2GHz (max unsigned 32bits),
linux time subsystem gets broken leading to the timeouts in displayport
programming. Ofc, my cpu runs at 4.7GHz.
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next prev parent reply other threads:[~2018-09-09 3:46 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-02 17:22 [Bug 107784] [AMD tahiti XT] displayport broken bugzilla-daemon
2018-09-02 17:28 ` bugzilla-daemon
2018-09-03 9:17 ` bugzilla-daemon
2018-09-03 10:30 ` bugzilla-daemon
2018-09-03 14:55 ` bugzilla-daemon
2018-09-05 7:19 ` bugzilla-daemon
2018-09-05 11:50 ` bugzilla-daemon
2018-09-05 12:28 ` bugzilla-daemon
2018-09-05 12:33 ` bugzilla-daemon
2018-09-05 13:38 ` sylvain.bertrand
2018-09-05 13:38 ` bugzilla-daemon
2018-09-05 17:44 ` bugzilla-daemon
2018-09-05 21:48 ` sylvain.bertrand
2018-09-05 21:48 ` bugzilla-daemon
2018-09-05 21:52 ` bugzilla-daemon
2018-09-05 21:54 ` bugzilla-daemon
2018-09-06 10:04 ` bugzilla-daemon
2018-09-06 12:31 ` sylvain.bertrand
2018-09-06 12:31 ` bugzilla-daemon
2018-09-06 14:22 ` bugzilla-daemon
2018-09-06 16:20 ` sylvain.bertrand
2018-09-06 16:20 ` bugzilla-daemon
2018-09-06 21:10 ` sylvain.bertrand
2018-09-07 21:48 ` sylvain.bertrand
2018-09-06 21:10 ` bugzilla-daemon
2018-09-07 21:48 ` bugzilla-daemon
2018-09-09 3:45 ` sylvain.bertrand [this message]
2018-09-09 3:46 ` bugzilla-daemon
2018-09-09 5:57 ` bugzilla-daemon
2018-09-09 13:05 ` bugzilla-daemon
2018-09-09 13:11 ` bugzilla-daemon
2018-09-09 14:59 ` sylvain.bertrand
2018-09-09 14:59 ` bugzilla-daemon
2018-09-10 5:20 ` bugzilla-daemon
2018-09-10 9:15 ` bugzilla-daemon
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