Fwd: [Bug 109051] intel_idle.max_cstate=1 required on baytrail to prevent crashes

[Paul Mansfield]

---------- Forwarded message ----------
From:  <bugzilla-daemon at bugzilla.kernel.org>
Date: 13 July 2016 at 04:01
Subject: [Bug 109051] intel_idle.max_cstate=1 required on baytrail to
prevent crashes



https://bugzilla.kernel.org/show_bug.cgi?id=109051

--- Comment #426 from andre.hoogendoorn at gmail.com ---
I have read the pdf and according to Intel, there is a C6 state hardware bug in
the CPU numbers as listed on page 9 and 10
----
VLP52 EOI Transactions May Not be Sent if Software Enters Core C6 During an
Interrupt Service Routine.

Problem:
If core C6 is entered after the start of an interrupt service routine but
before a write
to the APIC EOI (End of Interrupt) register, and the core is woken up by an
event
other than a fixed interrupt source the core may drop the EOI transaction the
next
time APIC EOI register is written and further interrupts from the same or lower
priority level will be blocked.

Implication:
EOI transactions may be lost and interrupts may be blocked when core C6 is used
during interrupt service routines.

Workaround:
It is possible for the firmware to contain a workaround for this erratum.