RE: [Xen-devel] ACPI suspend/resume on Dell Inspirons 1464/1564/1764

["Roger Cruz" <roger.cruz@xxxxxxxxxxxxxxxxxxx>]

A little more info.  I am now able to wake up the Dell Inspiron 1764 after I put it to sleep.  I found that the code commented out below would cause the problems in my system.  I have yet to understand why these variables don't end up with the expected values.  If anyone has any thoughts that they would like to share on how this code works and why it is comparing to stored variables, I would very much like to hear them.

Thank you
Roger R. Cruz


diff -r 6b2b1470f009 xen-3.4.2/xen/arch/x86/hvm/vmx/vmcs.c
--- a/xen-3.4.2/xen/arch/x86/hvm/vmx/vmcs.c
+++ b/xen-3.4.2/xen/arch/x86/hvm/vmx/vmcs.c

@@ -191,19 +192,25 @@
         cpu_has_vmx_ins_outs_instr_info = !!(vmx_basic_msr_high & (1U<<22));
         vmx_display_features();
     }
+#if 0
     else
     {
         /* Globals are already initialised: re-check them. */
         BUG_ON(vmcs_revision_id != vmx_basic_msr_low);
         BUG_ON(vmx_pin_based_exec_control != _vmx_pin_based_exec_control);
         BUG_ON(vmx_cpu_based_exec_control != _vmx_cpu_based_exec_control);
         BUG_ON(vmx_secondary_exec_control != _vmx_secondary_exec_control);
         BUG_ON(vmx_vmexit_control != _vmx_vmexit_control);
         BUG_ON(vmx_vmentry_control != _vmx_vmentry_control);
         BUG_ON(cpu_has_vmx_ins_outs_instr_info !=
                !!(vmx_basic_msr_high & (1U<<22)));
     }

+#endif
     /* IA-32 SDM Vol 3B: VMCS size is never greater than 4kB. */
     BUG_ON((vmx_basic_msr_high & 0x1fff) > PAGE_SIZE);


-----Original Message-----
From: Roger Cruz
Sent: Wed 5/12/2010 2:38 PM
To: Roger Cruz; xen-devel@xxxxxxxxxxxxxxxxxxx
Subject: RE: [Xen-devel] ACPI suspend/resume on Dell Inspirons 1464/1564/1764


We have made some progress in getting the inspiron laptops to work under Xen.  We tried xenunstable and xen-4.0.0 and discovered that xenunstable can resume whereas xen-4.0.0 cannot.  Through trial and error, we have been able to narrow down the actual changes that allowed it to work.  It looks like moving the trampoline code down from its 0x8c000 location allowed it to resume. 

So we took the change below and applied it to our 3.4.2 tree.  However, we still have a problem in our 3.4.2 tree with this patch applied.  If an HVM guest is running, the resume will fail with the exact same behavior as before.  Due to our environment setup, we have not been able to test xenunstable with an HVM guest, so we can't say if this problem is fixed in xenunstable or not.  Can someone familiar with these changes provide a clue as to what is going on?  how does having an HVM guest running affect the resume functionality?  Running PV linux guests does not affect resume, only HVM guests do.


--- old/xen-3.4.2/xen/include/asm-x86/config.h  2010-05-12 11:44:35.243564976 -0400
+++ new/xen-3.4.2/xen/include/asm-x86/config.h  2010-05-12 11:44:35.026578602 -0400
@@ -96,7 +96,7 @@
 /* Primary stack is restricted to 8kB by guard pages. */
 #define PRIMARY_STACK_SIZE 8192

-#define BOOT_TRAMPOLINE 0x8c000
+#define BOOT_TRAMPOLINE 0x7c000
 #define bootsym_phys(sym)                                 \
     (((unsigned long)&(sym)-(unsigned long)&trampoline_start)+BOOT_TRAMPOLINE)
 #define bootsym(sym)                                      \



--- old/xen-3.4.2/xen/include/asm-x86/config.h  2010-05-12 11:44:35.243564976 -0400
+++ new/xen-3.4.2/xen/include/asm-x86/config.h  2010-05-12 11:44:35.026578602 -0400
@@ -96,7 +96,7 @@
 /* Primary stack is restricted to 8kB by guard pages. */
 #define PRIMARY_STACK_SIZE 8192

-#define BOOT_TRAMPOLINE 0x8c000
+#define BOOT_TRAMPOLINE 0x7c000
 #define bootsym_phys(sym)                                 \
     (((unsigned long)&(sym)-(unsigned long)&trampoline_start)+BOOT_TRAMPOLINE)
 #define bootsym(sym)                                      \

-------

Hello fellow Xen developers,

I'm about to start debugging why Dell Inspirons running Xen 3.4.2 fail to resume after a suspend operation.  A colleague has also found that the problem exists on bare-metal Linux (https://bugs.launchpad.net/ubuntu/+source/linux/+bug/571422) and an upstream patch has been created (http://kernel.ubuntu.com/git?p=ubuntu/ubuntu-lucid.git;a=commitdiff;h=29c60ccc1a408371885d79d8f8c081fbcb9b10be). 

I would like to find out if anyone in the Xen community has encountered this problem and if a fix is in the works.  Otherwise, I will attempt to provide a similar solution to Linux's patch.

thanks
Roger

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