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

From: "H. Peter Anvin" <hpa@zytor.com>
To: "Cédric Godin" <cedric@belbone.be>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>,
	Len Brown <len.brown@intel.com>, Pavel Machek <pavel@ucw.cz>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>,
	x86@kernel.org, Linux Kernel <linux-kernel@vger.kernel.org>,
	linux-pm@vger.kernel.org
Subject: Re: [Bisected] 3.7-rc1 can't resume
Date: Thu, 18 Oct 2012 07:17:48 -0700	[thread overview]
Message-ID: <50800F8C.10600@zytor.com> (raw)
In-Reply-To: <507FF583.1070407@belbone.be>

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On 10/18/2012 05:26 AM, Cédric Godin wrote:
> Hello,
>
> After upgrading my kernel from 3.6 to 3.7-rc1 on my laptop, I can't resume anymore.
> I bisected the problem to
>

There is a fix for this already queued up.  Please try the attached 
patch to verify that it fixes your problem.

	-hpa

-- 
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel.  I don't speak on their behalf.


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>From 1396adc3c2bdc556d4cdd1cf107aa0b6d59fbb1e Mon Sep 17 00:00:00 2001
From: "H. Peter Anvin" <hpa@linux.intel.com>
Date: Mon, 1 Oct 2012 14:34:42 -0700
Subject: [PATCH] x86, suspend: Correct the restore of CR4, EFER; skip
 computing EFLAGS.ID

The patch:

    73201dbe x86, suspend: On wakeup always initialize cr4 and EFER

... was incorrectly committed in an intermediate (unfinished) form.

- We need to test CF, not ZF, for a bit test with btl.
- We don't actually need to compute the existence of EFLAGS.ID,
  since we set a flag at suspend time if CR4 should be restored.

Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Cc: Rafael J. Wysocki <rjw@sisk.pl>
Link: http://lkml.kernel.org/r/1348529239-17943-1-git-send-email-hpa@linux.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
 arch/x86/realmode/rm/wakeup_asm.S | 15 +++------------
 1 file changed, 3 insertions(+), 12 deletions(-)

diff --git a/arch/x86/realmode/rm/wakeup_asm.S b/arch/x86/realmode/rm/wakeup_asm.S
index e56479e..9e7e147 100644
--- a/arch/x86/realmode/rm/wakeup_asm.S
+++ b/arch/x86/realmode/rm/wakeup_asm.S
@@ -74,18 +74,9 @@ ENTRY(wakeup_start)
 
 	lidtl	wakeup_idt
 
-	/* Clear the EFLAGS but remember if we have EFLAGS.ID */
-	movl $X86_EFLAGS_ID, %ecx
-	pushl %ecx
-	popfl
-	pushfl
-	popl %edi
+	/* Clear the EFLAGS */
 	pushl $0
 	popfl
-	pushfl
-	popl %edx
-	xorl %edx, %edi
-	andl %ecx, %edi		/* %edi is zero iff CPUID & %cr4 are missing */
 
 	/* Check header signature... */
 	movl	signature, %eax
@@ -120,12 +111,12 @@ ENTRY(wakeup_start)
 	movl	%eax, %cr3
 
 	btl	$WAKEUP_BEHAVIOR_RESTORE_CR4, %edi
-	jz	1f
+	jnc	1f
 	movl	pmode_cr4, %eax
 	movl	%eax, %cr4
 1:
 	btl	$WAKEUP_BEHAVIOR_RESTORE_EFER, %edi
-	jz	1f
+	jnc	1f
 	movl	pmode_efer, %eax
 	movl	pmode_efer + 4, %edx
 	movl	$MSR_EFER, %ecx
-- 
1.7.11.7

