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Filename Latest commit message Latest commit date
Thomas Gleixner 49adaa60fa x86/hpet: Use common init for legacy clockevent
Replace the static initialization of the legacy clockevent with runtime
initialization utilizing the common init function as the last preparatory
step to switch the legacy clockevent over to the channel 0 storage in
hpet_base.

This comes with a twist. The static clockevent initializer has selected
support for periodic and oneshot mode unconditionally whether the HPET
config advertised periodic mode or not. Even the pre clockevents code did
this. But....

Using the conditional in hpet_init_clockevent() makes at least Qemu and one
hardware machine fail to boot.  There are two issues which cause the boot
failure:

 #1 After the timer delivery test in IOAPIC and the IOAPIC setup the next
    interrupt is not delivered despite the HPET channel being programmed
    correctly. Reprogramming the HPET after switching to IOAPIC makes it
    work again. After fixing this, the next issue surfaces:

 #2 Due to the unconditional periodic mode 'availability' the Local APIC
    timer calibration can hijack the global clockevents event handler
    without causing damage. Using oneshot at this stage makes if hang
    because the HPET does not get reprogrammed due to the handler
    hijacking. Duh, stupid me!

Both issues require major surgery and especially the kick HPET again after
enabling IOAPIC results in really nasty hackery.  This 'assume periodic
works' magic has survived since HPET support got added, so it's
questionable whether this should be fixed. Both Qemu and the failing
hardware machine support periodic mode despite the fact that both don't
advertise it in the configuration register and both need that extra kick
after switching to IOAPIC. Seems to be a feature...

Keep the 'assume periodic works' magic around and add a big fat comment.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Ingo Molnar <mingo@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ricardo Neri <ricardo.neri-calderon@linux.intel.com>
Cc: Ashok Raj <ashok.raj@intel.com>
Cc: Andi Kleen <andi.kleen@intel.com>
Cc: Suravee Suthikulpanit <Suravee.Suthikulpanit@amd.com>
Cc: Stephane Eranian <eranian@google.com>
Cc: Ravi Shankar <ravi.v.shankar@intel.com>
Link: https://lkml.kernel.org/r/20190623132436.646565913@linutronix.de
2019-06-28 00:57:27 +02:00
arch x86/hpet: Use common init for legacy clockevent 2019-06-28 00:57:27 +02:00
block block: fix page leak when merging to same page 2019-06-17 09:33:04 -06:00
certs
crypto treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
Documentation Char/Misc driver fixes for 5.2-rc6 2019-06-21 10:18:16 -07:00
drivers IOMMU Fix for v5.2-rc5: 2019-06-22 14:08:47 -07:00
fs More NFS client fixes for Linux 5.2 2019-06-21 13:45:41 -07:00
include Merge git://git.kernel.org/pub/scm/linux/kernel/git/davem/net 2019-06-21 22:23:35 -07:00
init Char/Misc driver fixes for 5.2-rc4 2019-06-08 12:50:36 -07:00
ipc treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 441 2019-06-05 17:37:17 +02:00
kernel SPDX update for 5.2-rc6 2019-06-21 09:58:42 -07:00
lib SPDX update for 5.2-rc6 2019-06-21 09:58:42 -07:00
LICENSES
mm treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
net Bluetooth: Fix regression with minimum encryption key size alignment 2019-06-22 09:07:39 -07:00
samples SPDX update for 5.2-rc6 2019-06-21 09:58:42 -07:00
scripts treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 505 2019-06-19 17:11:22 +02:00
security SPDX update for 5.2-rc6 2019-06-21 09:58:42 -07:00
sound treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 500 2019-06-19 17:09:55 +02:00
tools SPDX update for 5.2-rc6 2019-06-21 09:58:42 -07:00
usr
virt SPDX update for 5.2-rc6 2019-06-21 09:58:42 -07:00
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap MAINTAINERS: Update my email address 2019-06-18 14:37:27 +01:00
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS Char/Misc driver fixes for 5.2-rc6 2019-06-21 10:18:16 -07:00
Makefile Linux 5.2-rc6 2019-06-22 16:01:36 -07:00
README

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.