linux-kernel - Re: [Bisected] 3.7-rc1 can't resume

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Message-ID: <20130223131856.GA682@onny>
Date:	Sat, 23 Feb 2013 13:18:56 +0000
From:	Jonas Heinrich <onny@...ject-insanity.org>
To:	"H. Peter Anvin" <hpa@...or.com>, len.brown@...el.com,
	pavel@....cz, tglx@...utronix.de, mingo@...hat.com, x86@...nel.org,
	rjw@...k.pl
Cc:	linux-kernel@...r.kernel.org, linux-pm@...r.kernel.org
Subject: Re: [Bisected] 3.7-rc1 can't resume

Hi,
thank you for your replay and the effort you invest in helping me out
with this problem.
Today, I further debuged the problem and reverted this part of your commit
(without understanding the actual code):

diff --git a/arch/x86/realmode/rm/wakeup_asm.S b/arch/x86/realmode/rm/wakeup_asm.S
index 8905166..e56479e 100644
--- a/arch/x86/realmode/rm/wakeup_asm.S
+++ b/arch/x86/realmode/rm/wakeup_asm.S
@@ -110,15 +119,15 @@  ENTRY(wakeup_start)
 	movl	pmode_cr3, %eax
 	movl	%eax, %cr3
 
-	movl	pmode_cr4, %ecx
-	jecxz	1f
-	movl	%ecx, %cr4
+	btl	$WAKEUP_BEHAVIOR_RESTORE_CR4, %edi
+	jz	1f
+	movl	pmode_cr4, %eax
+	movl	%eax, %cr4
 1:
+	btl	$WAKEUP_BEHAVIOR_RESTORE_EFER, %edi
+	jz	1f
 	movl	pmode_efer, %eax
 	movl	pmode_efer + 4, %edx
-	movl	%eax, %ecx
-	orl	%edx, %ecx
-	jz	1f
 	movl	$MSR_EFER, %ecx
 	wrmsr
 1:

I applied this change to the current 3.8 kernel and it worked!
If you need more test results, just send me patches and I'll try them :)

Best regards,
Jonas

On 02-18 08:21, H. Peter Anvin wrote:
> I might be able to get my hands on a T43 later this week and see if I can reproduce this.  This patch seems more plausible, at least... but still puzzling.
> 
> Jonas Heinrich <onny@...ject-insanity.org> wrote:
> 
> >On 02-17 21:40, Rafael J. Wysocki wrote:
> >> Does the commit immediately preceding this one behave correctly?
> >Strangely the preceding commit works well, so I bisected the kernel
> >again, this time more carefully and I've got a different result!
> >(see bisect_log attachement).
> >It seems to be commit 73201dbec64aebf6b0dca855b523f437972dc7bb 
> >(https://patchwork.kernel.org/patch/1511921/).
> >Someone on LKML already reported an issue with this commit
> >(https://lkml.org/lkml/2012/10/18/228) , but Peter
> >Anvins patch got already applied in newer versions.
> >Reverting this patch with the recent git clone seems to be difficult
> >because it already has too much dependencies.
> >
> >Additionally I've included dmesg dumps of the last good and the bad
> >kernel version.
> >
> >On 02-17 12:52, H. Peter Anvin wrote:
> >> T43 is quite old... which might have exposed unique bugs.  How
> >reliable is the failure?  Even one misidentified commit results in git
> >bisect giving garbage.
> >It affects really all versions after that commit and the failure
> >happens
> >every time I try to resume my notebook.
> >
> >Best regards,
> >Jonas
> 
> -- 
> Sent from my mobile phone. Please excuse brevity and lack of formatting.

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