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* [PATCH v2 0/2] i8253: Fix PIT shutdown quirk on Hyper-V
@ 2018-11-04  3:48 Michael Kelley
  2018-11-04  3:48 ` [PATCH v2 1/2] i8253: Add support for PIT shutdown quirk Michael Kelley
  2018-11-04  3:48 ` [PATCH v2 2/2] x86/hyper-v: Enable " Michael Kelley
  0 siblings, 2 replies; 7+ messages in thread
From: Michael Kelley @ 2018-11-04  3:48 UTC (permalink / raw)
  To: gregkh, devel, linux-kernel, tglx, daniel.lezcano,
	virtualization, jgross, akataria, olaf, apw, vkuznets, jasowang,
	marcelo.cerri, KY Srinivasan
  Cc: Michael Kelley

pit_shutdown() doesn't work on Hyper-V because of a quirk in the
PIT emulation. This problem exists in all versions of Hyper-V and
had not been noticed previously. When the counter register is set
to zero, the emulated PIT continues to interrupt @18.2 HZ.

Account for this quirk by adding a global variable in the i8253
code that controls whether the counter register is zero'ed. Then
in Hyper-V initialization code, override the default setting so
the counter register is not zero'ed.

Changes in v2:
* Instead of a function call to check if running on Hyper-V,
use a global variable to control whether the counter register
is zero'ed. [Juergen Gross & Thomas Gleixner]

Michael Kelley (2):
  i8253: Add support for PIT shutdown quirk
  x86/hyper-v: Enable PIT shutdown quirk

 arch/x86/kernel/cpu/mshyperv.c | 11 +++++++++++
 drivers/clocksource/i8253.c    | 14 ++++++++++++--
 include/linux/i8253.h          |  1 +
 3 files changed, 24 insertions(+), 2 deletions(-)

-- 
1.8.3.1


^ permalink raw reply	[flat|nested] 7+ messages in thread

end of thread, other threads:[~2018-11-04 10:11 UTC | newest]

Thread overview: 7+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2018-11-04  3:48 [PATCH v2 0/2] i8253: Fix PIT shutdown quirk on Hyper-V Michael Kelley
2018-11-04  3:48 ` [PATCH v2 1/2] i8253: Add support for PIT shutdown quirk Michael Kelley
2018-11-04 10:09   ` [tip:x86/urgent] clockevents/drivers/i8253: " tip-bot for Michael Kelley
2018-11-04 10:09   ` tip-bot for Michael Kelley
2018-11-04  3:48 ` [PATCH v2 2/2] x86/hyper-v: Enable " Michael Kelley
2018-11-04 10:10   ` [tip:x86/urgent] " tip-bot for Michael Kelley
2018-11-04 10:10   ` tip-bot for Michael Kelley

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