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To:     linux-kernel@vger.kernel.org
Cc:     peterz@infradead.org, tglx@linutronix.de,
        rafael.j.wysocki@intel.com, len.brown@intel.com, rjw@rjwysocki.net,
        diego.viola@gmail.com, rui.zhang@intel.com,
        viktor_jaegerskuepper@freenet.de
From:   Siegfried Metz <frame@mailbox.org>
Subject: REGRESSION: boot stalls on several old dual core Intel CPUs
Message-ID: <74c5abc8-7430-5bc9-2f8a-a2205608bee7@mailbox.org>
Date:   Thu, 30 Aug 2018 12:55:30 +0200
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Dear kernel developers,

since mainline kernel 4.18 (up to the latest mainline kernel 4.18.5)
Intel Core 2 Duo processors are affected by boot stalling early in the
boot process. As it is so early there is no dmesg output (or any log).

A few users in the Arch Linux community used git bisect and tracked the
issue down to this the bad commit:
7197e77abcb65a71d0b21d67beb24f153a96055e clocksource: Remove kthread

Either reverting the bad commit or as a workaround using an additional
kernel boot parameter "clocksource=hpet" has been successfully used to
boot with Intel Core 2 processors and avoid the stalling.

clocksource= options parameters are one of "tsc", "hpet", "acpi_pm",
most of the time hpet did the trick.


Additional information:
Kernel 4.17.19 is unaffected by this issues, kernel 4.18 series and
4.19-rc1 are still affected.

Also there is the bug-report:
https://bugzilla.kernel.org/show_bug.cgi?id=200957
and a duplicate one:
https://bugzilla.kernel.org/show_bug.cgi?id=200959


Thanks for fixing this issue.

Siegfried