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Re: [Xen-devel] S3 resume issues

On Wed, Jan 2, 2013 at 10:15 AM, Malcolm Crossley <malcolm.crossley@xxxxxxxxxx> wrote:
Hi Ben,

On 02/01/13 13:08, Ben Guthro wrote:
I'm starting a new thread on this, to attempt to not confuse this issue, with the other S3 issue reported by Marek Marczykowski against 4.1
If you prefer I continue that thread instead, please let me know, and I will be happy to do so.

Some background:
I am attempting to chase down yet another S3 issue in the Xen-4.2 / unstable tree, seen on some (but not all) platforms.
The particular machine I am able to reproduce it 100% of the time is a Lenovo T430 (Ivy bridge laptop)

To help reproduce the issue it would be good to know what Linux kernel you were using.

Currently, XenClient Enterprise is using a kernel based off of the ubuntu "precise" 3.2 kernel - 

However, we have a number of patches on top of this - one specific for S3 is Konrad's older patches (attached acpi-s3.v9.patch)

That said, I have also tested with the latest kernel.org kernel, as we maintain a set of patches against the tip of development, as well.
This same failure has been seen with the latest kernel, as well as the latest xen-unstable code

To minimize variables, I've stuck with the known failure case of Xen-4.2.y and linux-3.2

Also, Does Xen-4.1 work on this particular machine? If Xen-4.1 does not work, have you confirmed that baremetal suspend resume works? (I'm just covering the base's here)

I have not tested 4.1 - but Xen 4.0.3 works with this same kernel.
I have not tested bare metal, as I am reasonably convinced it is the hypervisor, since Xen-4.0.3 works

I also notice that the laptop can have NVIDIA optimus technology. Does this particular T430 have an Nvidia GPU? Is there a way to force disable the NVIDIA GPU in the BIOS, this may help with displaying resume progress via the display.

Optimus is not a factor in this case - this machine is Intel GPU only.

The symptoms of the failure are that it suspends just fine, but does not resume.
When attempting to resume, by pressing the power button - the disk LED flashes, and the CDROM activity LED flashes, but then the system seems to put itsself back to sleep, as the power LED goes back to pulsing
Note that the soft pulsing LED is distinctly different from the crash LED blink rate.
Is there any sign of the video POSTING (flickering screen etc) ?

No screen flicker, only the LED activity mentioned above

I have tried a number of the tricks Jan suggested to me the last time we were down this path - so far to no success.
The failure seems to be happening so soon in the resume process, that there is not yet a console available.

I have resorted to putting BUG() in the code directly in the resume path, in an attempt to understand what is going on - since there seems to be something in this path that I don't fully understand.

In xen/arch/x86/acpi/power.c - acpi_enter_sleep_state() seems to be the code that actually puts the processor into S3.
If I put a BUG() directly before the return of this function - I never seem to reach this. It continues to pulse the power LED, as described above.
I would have expected a hypervisor crash upon attempting to wake up the system.

The actual wakeup vector is wakeup_start in xen/arch/x86/boot/wakeup.S

I'll take a look at this, thanks for the pointer.


Attachment: acpi-s3.v9.patch
Description: Binary data

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