On Wed, Aug 28, 2019 at 11:11:55AM +0200, Greg KH wrote:
On Wed, Aug 28, 2019 at 05:00:44PM +0800, Yu Chen wrote:
On Wed, Aug 28, 2019 at 10:43:51AM +0200, Greg KH wrote:
> On Wed, Aug 28, 2019 at 12:12:39AM -0400, Sasha Levin wrote:
> > This is a note to let you know that I've just added the patch titled
> >
> > x86/pm: Introduce quirk framework to save/restore extra MSR registers
around suspend/resume
> >
> > to the 4.4-stable tree which can be found at:
> >
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
> >
> > The filename of the patch is:
> > x86-pm-introduce-quirk-framework-to-save-restore-ext.patch
> > and it can be found in the queue-4.4 subdirectory.
> >
> > If you, or anyone else, feels it should not be added to the stable tree,
> > please let <sta...@vger.kernel.org> know about it.
> >
> >
> >
> > commit d63273440aa0fdebc30d0c931f15f79beb213134
> > Author: Chen Yu <yu.c.c...@intel.com>
> > Date: Wed Nov 25 01:03:41 2015 +0800
> >
> > x86/pm: Introduce quirk framework to save/restore extra MSR registers
around suspend/resume
> >
> > A bug was reported that on certain Broadwell platforms, after
> > resuming from S3, the CPU is running at an anomalously low
> > speed.
> >
> > It turns out that the BIOS has modified the value of the
> > THERM_CONTROL register during S3, and changed it from 0 to 0x10,
> > thus enabled clock modulation(bit4), but with undefined CPU Duty
> > Cycle(bit1:3) - which causes the problem.
> >
> > Here is a simple scenario to reproduce the issue:
> >
> > 1. Boot up the system
> > 2. Get MSR 0x19a, it should be 0
> > 3. Put the system into sleep, then wake it up
> > 4. Get MSR 0x19a, it shows 0x10, while it should be 0
> >
> > Although some BIOSen want to change the CPU Duty Cycle during
> > S3, in our case we don't want the BIOS to do any modification.
> >
> > Fix this issue by introducing a more generic x86 framework to
> > save/restore specified MSR registers(THERM_CONTROL in this case)
> > for suspend/resume. This allows us to fix similar bugs in a much
> > simpler way in the future.
> >
> > When the kernel wants to protect certain MSRs during suspending,
> > we simply add a quirk entry in msr_save_dmi_table, and customize
> > the MSR registers inside the quirk callback, for example:
> >
> > u32 msr_id_need_to_save[] = {MSR_ID0, MSR_ID1, MSR_ID2...};
> >
> > and the quirk mechanism ensures that, once resumed from suspend,
> > the MSRs indicated by these IDs will be restored to their
> > original, pre-suspend values.
> >
> > Since both 64-bit and 32-bit kernels are affected, this patch
> > covers the common 64/32-bit suspend/resume code path. And
> > because the MSRs specified by the user might not be available or
> > readable in any situation, we use rdmsrl_safe() to safely save
> > these MSRs.
> >
> > Reported-and-tested-by: Marcin Kaszewski <marcin.kaszew...@intel.com>
> > Signed-off-by: Chen Yu <yu.c.c...@intel.com>
> > Acked-by: Rafael J. Wysocki <rafael.j.wyso...@intel.com>
> > Acked-by: Pavel Machek <pa...@ucw.cz>
> > Cc: Andy Lutomirski <l...@amacapital.net>
> > Cc: Borislav Petkov <b...@alien8.de>
> > Cc: Brian Gerst <brge...@gmail.com>
> > Cc: Denys Vlasenko <dvlas...@redhat.com>
> > Cc: H. Peter Anvin <h...@zytor.com>
> > Cc: Linus Torvalds <torva...@linux-foundation.org>
> > Cc: Peter Zijlstra <pet...@infradead.org>
> > Cc: Thomas Gleixner <t...@linutronix.de>
> > Cc: b...@suse.de
> > Cc: len.br...@intel.com
> > Cc: li...@horizon.com
> > Cc: l...@kernel.org
> > Cc: r...@rjwysocki.net
> > Link:
http://lkml.kernel.org/r/c9abdcbc173dd2f57e8990e304376f19287e92ba.1448382971.git.yu.c.c...@intel.com
> > [ More edits to the naming of data structures. ]
> > Signed-off-by: Ingo Molnar <mi...@kernel.org>
>
> No git id of the patch in Linus's tree, or your signed-off-by?
>
I think the commit id in Linus'tree should be
7a9c2dd08eadd5c6943115dbbec040c38d2e0822
Ah, and Sasha added it because a later patch needed it :(
Sasha, can you fix this patch's headers up to be in the "proper" format?
Yes, I brought it in as a dependency but cherry picked instead of using
my scripts by mistake. I'll fix up the patch in the queue.
--
Thanks,
Sasha
