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 <[email protected]> know about it. > > > > > > > > > > > > commit d63273440aa0fdebc30d0c931f15f79beb213134 > > > Author: Chen Yu <[email protected]> > > > 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 <[email protected]> > > > Signed-off-by: Chen Yu <[email protected]> > > > Acked-by: Rafael J. Wysocki <[email protected]> > > > Acked-by: Pavel Machek <[email protected]> > > > Cc: Andy Lutomirski <[email protected]> > > > Cc: Borislav Petkov <[email protected]> > > > Cc: Brian Gerst <[email protected]> > > > Cc: Denys Vlasenko <[email protected]> > > > Cc: H. Peter Anvin <[email protected]> > > > Cc: Linus Torvalds <[email protected]> > > > Cc: Peter Zijlstra <[email protected]> > > > Cc: Thomas Gleixner <[email protected]> > > > Cc: [email protected] > > > Cc: [email protected] > > > Cc: [email protected] > > > Cc: [email protected] > > > Cc: [email protected] > > > 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 <[email protected]> > > > > 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? thanks, greg k-h
