VT-d and x2apic: broken resume after suspend to ram

VT-d and x2apic: broken resume after suspend to ram

[Peter Senna Tschudin]

I have one notebook that is failing to resume after suspend to ram.
I've filled a bug report back on the 2.6.41 days:

https://bugzilla.redhat.com/show_bug.cgi?id=787299

The issue is that trying to resume after suspending to ram freezes the
computer. The resume starts well, but then it hangs.

Yesterday I found that this may be related to VT-d / x2apic. If I
disable VT-d on the BIOS, suspend / resume works fine. If I enable
VT-d and pass nox2apic as boot parameter to Kernel suspend and resume
works fine. I would like some pointers to fix this issue. Can you help
me?

Only when I have VT-d enabled, dmesg gives me additional output:
[    0.023913] IOAPIC id 2 under DRHD base  0xfed91000 IOMMU 1
[    0.024080] Enabled IRQ remapping in x2apic mode
[    0.024081] Enabling x2apic
[    0.024082] Enabled x2apic
[    0.024087] Switched APIC routing to cluster x2apic.

The notebook is Toshiba R830-10p with i7-2620M.

Thanks!
-- 
Peter

Re: VT-d and x2apic: broken resume after suspend to ram

[Joerg Roedel]

Hi Peter,

On Fri, Nov 01, 2013 at 01:37:36PM +0100, Peter Senna Tschudin wrote:
> I have one notebook that is failing to resume after suspend to ram.
> I've filled a bug report back on the 2.6.41 days:
> 
> https://bugzilla.redhat.com/show_bug.cgi?id=787299
> 
> The issue is that trying to resume after suspending to ram freezes the
> computer. The resume starts well, but then it hangs.
> 
> Yesterday I found that this may be related to VT-d / x2apic. If I
> disable VT-d on the BIOS, suspend / resume works fine. If I enable
> VT-d and pass nox2apic as boot parameter to Kernel suspend and resume
> works fine. I would like some pointers to fix this issue. Can you help
> me?
> 
> Only when I have VT-d enabled, dmesg gives me additional output:
> [    0.023913] IOAPIC id 2 under DRHD base  0xfed91000 IOMMU 1
> [    0.024080] Enabled IRQ remapping in x2apic mode
> [    0.024081] Enabling x2apic
> [    0.024082] Enabled x2apic
> [    0.024087] Switched APIC routing to cluster x2apic.
> 
> The notebook is Toshiba R830-10p with i7-2620M.

Which kernels have you tried? Does it happen with all of them or is
there a kernel-version where this started?


	Joerg

Re: VT-d and x2apic: broken resume after suspend to ram

[Peter Senna Tschudin]

On Fri, Nov 1, 2013 at 2:07 PM, Joerg Roedel <joro@8bytes.org> wrote:
> Hi Peter,
>
> On Fri, Nov 01, 2013 at 01:37:36PM +0100, Peter Senna Tschudin wrote:
>> I have one notebook that is failing to resume after suspend to ram.
>> I've filled a bug report back on the 2.6.41 days:
>>
>> https://bugzilla.redhat.com/show_bug.cgi?id=787299
>>
>> The issue is that trying to resume after suspending to ram freezes the
>> computer. The resume starts well, but then it hangs.
>>
>> Yesterday I found that this may be related to VT-d / x2apic. If I
>> disable VT-d on the BIOS, suspend / resume works fine. If I enable
>> VT-d and pass nox2apic as boot parameter to Kernel suspend and resume
>> works fine. I would like some pointers to fix this issue. Can you help
>> me?
>>
>> Only when I have VT-d enabled, dmesg gives me additional output:
>> [    0.023913] IOAPIC id 2 under DRHD base  0xfed91000 IOMMU 1
>> [    0.024080] Enabled IRQ remapping in x2apic mode
>> [    0.024081] Enabling x2apic
>> [    0.024082] Enabled x2apic
>> [    0.024087] Switched APIC routing to cluster x2apic.
>>
>> The notebook is Toshiba R830-10p with i7-2620M.
>
> Which kernels have you tried? Does it happen with all of them or is
> there a kernel-version where this started?

I'm using 3.11.6-200.fc19.x86_64. I always had VT-d enabled, and
suspend / resume never worked on Linux. I did not know that disabling
VT-d could be a workaround to the resume issue until yesterday.

Does this have anything in common to:
https://bugzilla.redhat.com/show_bug.cgi?id=752613

>
>
>         Joerg
>
>



-- 
Peter

Re: VT-d and x2apic: broken resume after suspend to ram

[Joerg Roedel]

On Fri, Nov 01, 2013 at 02:21:07PM +0100, Peter Senna Tschudin wrote:
> On Fri, Nov 1, 2013 at 2:07 PM, Joerg Roedel <joro-zLv9SwRftAIdnm+yROfE0A@public.gmane.org> wrote:
> > Which kernels have you tried? Does it happen with all of them or is
> > there a kernel-version where this started?
> 
> I'm using 3.11.6-200.fc19.x86_64. I always had VT-d enabled, and
> suspend / resume never worked on Linux. I did not know that disabling
> VT-d could be a workaround to the resume issue until yesterday.
> 
> Does this have anything in common to:
> https://bugzilla.redhat.com/show_bug.cgi?id=752613

This is probably not related. As far as I can see this issue was about
boot problem with discrete graphics while your problem is related to
suspend/resume.

The next thing I would try on your machine is to get some kernel debug
messages from resume. This might be hard to get, since your notebook
has probably no serial port. But you can try to boot with
no_console_suspend on the kernel cmdline and see if it gives you any
output on resume.

Maybe some of the VT-d guys can take a look too?


	Joerg

Re: VT-d and x2apic: broken resume after suspend to ram

[Peter Senna Tschudin]

On Fri, Nov 1, 2013 at 3:21 PM, Joerg Roedel <joro@8bytes.org> wrote:
> On Fri, Nov 01, 2013 at 02:21:07PM +0100, Peter Senna Tschudin wrote:
>> On Fri, Nov 1, 2013 at 2:07 PM, Joerg Roedel <joro@8bytes.org> wrote:
>> > Which kernels have you tried? Does it happen with all of them or is
>> > there a kernel-version where this started?
>>
>> I'm using 3.11.6-200.fc19.x86_64. I always had VT-d enabled, and
>> suspend / resume never worked on Linux. I did not know that disabling
>> VT-d could be a workaround to the resume issue until yesterday.
>>
>> Does this have anything in common to:
>> https://bugzilla.redhat.com/show_bug.cgi?id=752613
>
> This is probably not related. As far as I can see this issue was about
> boot problem with discrete graphics while your problem is related to
> suspend/resume.
>
> The next thing I would try on your machine is to get some kernel debug
> messages from resume. This might be hard to get, since your notebook
> has probably no serial port. But you can try to boot with
> no_console_suspend on the kernel cmdline and see if it gives you any
> output on resume.
Only serial ports over USB:
usb 2-1.3.2: pl2303 converter now attached to ttyUSB0

The issue with no_console_suspend is that the monitor is powered off
on suspend and never resume after that. The external monitor enters in
power save mode during suspend and also never resume. Do you know if
replacing my wifi/bt card by this:

http://www.startech.com/Cards-Adapters/Serial-Cards-Adapters/2-Port-RS232-Mini-PCI-Express-Serial-Card-16950-UART~MPEX2S952

would enable to use the serial console for seeing kernel debug messages?

>
> Maybe some of the VT-d guys can take a look too?
>
>
>         Joerg
>



-- 
Peter

Re: VT-d and x2apic: broken resume after suspend to ram

[Joerg Roedel]

On Fri, Nov 01, 2013 at 04:47:47PM +0100, Peter Senna Tschudin wrote:
> Only serial ports over USB:
> usb 2-1.3.2: pl2303 converter now attached to ttyUSB0
> 
> The issue with no_console_suspend is that the monitor is powered off
> on suspend and never resume after that. The external monitor enters in
> power save mode during suspend and also never resume. Do you know if
> replacing my wifi/bt card by this:
> 
> http://www.startech.com/Cards-Adapters/Serial-Cards-Adapters/2-Port-RS232-Mini-PCI-Express-Serial-Card-16950-UART~MPEX2S952
> 
> would enable to use the serial console for seeing kernel debug messages?

Who knows, depends on the BIOS in your machine, I guess. But I would say
there is a at least a better chance with this than with a USB-Serial
adapter.


	Joerg