i915: RC6 causes sudden shutdowns

i915: RC6 causes sudden shutdowns

[Patrik Kullman]

Hi,

I recently acquired the Asus Zenbook UX31E but have been looking for
ways to extend the battery life.

I read that the i915_enable_rc6 parameter could decrease power usage
significantly and tried it with the 3.1.1 and 3.1.2 kernels, and
indeed it does.
However, I (and the other Zenbook-owners from the Ubuntu forums)
experience sudden, unexpected shutdowns (for me, 1-4 times per day)
with this parameter.
It's as sudden as a power loss.

It happens both when pcie_aspm=force is supplied and when it's not.
What also is a bit concerning is that I read that RC6 is going to be
enabled by default from 3.2 onward?

How would we go about troubleshooting this?

Or is the only option to blacklist the machine from RC6 if it doesn't
work as is?

Re: i915: RC6 causes sudden shutdowns

[Patrik Kullman]

So is this being worked on already?

It would be wonderful to get this fixed since it gives additional
hours of battery life, but it's currently unusable for my this
machine.

2011/11/24 Patrik Kullman <patrik.kullman@gmail.com>:
> Hi,
>
> I recently acquired the Asus Zenbook UX31E but have been looking for
> ways to extend the battery life.
>
> I read that the i915_enable_rc6 parameter could decrease power usage
> significantly and tried it with the 3.1.1 and 3.1.2 kernels, and
> indeed it does.
> However, I (and the other Zenbook-owners from the Ubuntu forums)
> experience sudden, unexpected shutdowns (for me, 1-4 times per day)
> with this parameter.
> It's as sudden as a power loss.
>
> It happens both when pcie_aspm=force is supplied and when it's not.
> What also is a bit concerning is that I read that RC6 is going to be
> enabled by default from 3.2 onward?
>
> How would we go about troubleshooting this?
>
> Or is the only option to blacklist the machine from RC6 if it doesn't
> work as is?

Re: i915: RC6 causes sudden shutdowns

[Andy Lutomirski]

On 11/23/2011 03:43 PM, Patrik Kullman wrote:
> Hi,
> 
> I recently acquired the Asus Zenbook UX31E but have been looking for
> ways to extend the battery life.
> 
> I read that the i915_enable_rc6 parameter could decrease power usage
> significantly and tried it with the 3.1.1 and 3.1.2 kernels, and
> indeed it does.
> However, I (and the other Zenbook-owners from the Ubuntu forums)
> experience sudden, unexpected shutdowns (for me, 1-4 times per day)
> with this parameter.
> It's as sudden as a power loss.

Do you have DMAR enabled?  If so, it's a known problem and it's being
worked on (and the default will not change for you AFAICT).  If not, you
should send a bug report to the intel-gfx -- several people there care
about this.

--Andy

Re: i915: RC6 causes sudden shutdowns

[Patrik Kullman]

2011/12/1 Andy Lutomirski <luto@mit.edu>:
> On 11/23/2011 03:43 PM, Patrik Kullman wrote:
>> Hi,
>>
>> I recently acquired the Asus Zenbook UX31E but have been looking for
>> ways to extend the battery life.
>>
>> I read that the i915_enable_rc6 parameter could decrease power usage
>> significantly and tried it with the 3.1.1 and 3.1.2 kernels, and
>> indeed it does.
>> However, I (and the other Zenbook-owners from the Ubuntu forums)
>> experience sudden, unexpected shutdowns (for me, 1-4 times per day)
>> with this parameter.
>> It's as sudden as a power loss.
>
> Do you have DMAR enabled?  If so, it's a known problem and it's being
> worked on (and the default will not change for you AFAICT).  If not, you
> should send a bug report to the intel-gfx -- several people there care
> about this.
>
> --Andy

Well, it's not something I've explicitly enabled.

Is it on by default?

If so, any reason why I wouldn't want to disable it?

Re: i915: RC6 causes sudden shutdowns

[Andrew Lutomirski]

On Thu, Dec 1, 2011 at 9:00 PM, Patrik Kullman <patrik.kullman@gmail.com> wrote:
> 2011/12/1 Andy Lutomirski <luto@mit.edu>:
>> On 11/23/2011 03:43 PM, Patrik Kullman wrote:
>>> Hi,
>>>
>>> I recently acquired the Asus Zenbook UX31E but have been looking for
>>> ways to extend the battery life.
>>>
>>> I read that the i915_enable_rc6 parameter could decrease power usage
>>> significantly and tried it with the 3.1.1 and 3.1.2 kernels, and
>>> indeed it does.
>>> However, I (and the other Zenbook-owners from the Ubuntu forums)
>>> experience sudden, unexpected shutdowns (for me, 1-4 times per day)
>>> with this parameter.
>>> It's as sudden as a power loss.
>>
>> Do you have DMAR enabled?  If so, it's a known problem and it's being
>> worked on (and the default will not change for you AFAICT).  If not, you
>> should send a bug report to the intel-gfx -- several people there care
>> about this.
>>
>> --Andy
>
> Well, it's not something I've explicitly enabled.
>
> Is it on by default?

Depends on config options.  You can probably get a good idea by
looking for "DMAR" in your kernel log.

>
> If so, any reason why I wouldn't want to disable it?

There are three reasons to enable it:

1. If you're paranoid and want to (partially) protect your system
against malicious PCI/PCIe cards.
2. If you assign devices in your system to VM guests.
3. If you have more than 4GB of RAM and you have DMA-capable devices
that can only address 32 bits, then you might get a performance boost.

In other words, for normal desktop use, you don't need it.  Try
booting with intel_iommu=off.

--Andy

Re: i915: RC6 causes sudden shutdowns

[Patrik Kullman]

2011/12/2 Andrew Lutomirski <luto@mit.edu>:
> On Thu, Dec 1, 2011 at 9:00 PM, Patrik Kullman <patrik.kullman@gmail.com> wrote:
>> 2011/12/1 Andy Lutomirski <luto@mit.edu>:
>>> On 11/23/2011 03:43 PM, Patrik Kullman wrote:
>>>> Hi,
>>>>
>>>> I recently acquired the Asus Zenbook UX31E but have been looking for
>>>> ways to extend the battery life.
>>>>
>>>> I read that the i915_enable_rc6 parameter could decrease power usage
>>>> significantly and tried it with the 3.1.1 and 3.1.2 kernels, and
>>>> indeed it does.
>>>> However, I (and the other Zenbook-owners from the Ubuntu forums)
>>>> experience sudden, unexpected shutdowns (for me, 1-4 times per day)
>>>> with this parameter.
>>>> It's as sudden as a power loss.
>>>
>>> Do you have DMAR enabled?  If so, it's a known problem and it's being
>>> worked on (and the default will not change for you AFAICT).  If not, you
>>> should send a bug report to the intel-gfx -- several people there care
>>> about this.
>>>
>>> --Andy
>>
>> Well, it's not something I've explicitly enabled.
>>
>> Is it on by default?
>
> Depends on config options.  You can probably get a good idea by
> looking for "DMAR" in your kernel log.
>
>>
>> If so, any reason why I wouldn't want to disable it?
>
> There are three reasons to enable it:
>
> 1. If you're paranoid and want to (partially) protect your system
> against malicious PCI/PCIe cards.
> 2. If you assign devices in your system to VM guests.
> 3. If you have more than 4GB of RAM and you have DMA-capable devices
> that can only address 32 bits, then you might get a performance boost.
>
> In other words, for normal desktop use, you don't need it.  Try
> booting with intel_iommu=off.
>
> --Andy

As reported by another Ubuntu Zenbook user
(http://ubuntuforums.org/showpost.php?p=11507684&postcount=207):

Sadly i still get random shutdowns with 3.2-rc4. I have noticed that
if i just leave my computer on, and does not use it (i have disabled
the screensaver), the crashes does not accrue.

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash drm.debug=4 intel_iommu=off
i915.modeset=1 i915.i915_enable_fbc=1 i915.lvds_downclock=1
i915.i915_enable_rc6=1 pcie_aspm=force"

Re: i915: RC6 causes sudden shutdowns

[Patrik Kullman]

2011/12/3 Patrik Kullman <patrik.kullman@gmail.com>:
> 2011/12/2 Andrew Lutomirski <luto@mit.edu>:
>> On Thu, Dec 1, 2011 at 9:00 PM, Patrik Kullman <patrik.kullman@gmail.com> wrote:
>>> 2011/12/1 Andy Lutomirski <luto@mit.edu>:
>>>> On 11/23/2011 03:43 PM, Patrik Kullman wrote:
>>>>> Hi,
>>>>>
>>>>> I recently acquired the Asus Zenbook UX31E but have been looking for
>>>>> ways to extend the battery life.
>>>>>
>>>>> I read that the i915_enable_rc6 parameter could decrease power usage
>>>>> significantly and tried it with the 3.1.1 and 3.1.2 kernels, and
>>>>> indeed it does.
>>>>> However, I (and the other Zenbook-owners from the Ubuntu forums)
>>>>> experience sudden, unexpected shutdowns (for me, 1-4 times per day)
>>>>> with this parameter.
>>>>> It's as sudden as a power loss.
>>>>
>>>> Do you have DMAR enabled?  If so, it's a known problem and it's being
>>>> worked on (and the default will not change for you AFAICT).  If not, you
>>>> should send a bug report to the intel-gfx -- several people there care
>>>> about this.
>>>>
>>>> --Andy
>>>
>>> Well, it's not something I've explicitly enabled.
>>>
>>> Is it on by default?
>>
>> Depends on config options.  You can probably get a good idea by
>> looking for "DMAR" in your kernel log.
>>
>>>
>>> If so, any reason why I wouldn't want to disable it?
>>
>> There are three reasons to enable it:
>>
>> 1. If you're paranoid and want to (partially) protect your system
>> against malicious PCI/PCIe cards.
>> 2. If you assign devices in your system to VM guests.
>> 3. If you have more than 4GB of RAM and you have DMA-capable devices
>> that can only address 32 bits, then you might get a performance boost.
>>
>> In other words, for normal desktop use, you don't need it.  Try
>> booting with intel_iommu=off.
>>
>> --Andy
>
> As reported by another Ubuntu Zenbook user
> (http://ubuntuforums.org/showpost.php?p=11507684&postcount=207):
>
> Sadly i still get random shutdowns with 3.2-rc4. I have noticed that
> if i just leave my computer on, and does not use it (i have disabled
> the screensaver), the crashes does not accrue.
>
> GRUB_CMDLINE_LINUX_DEFAULT="quiet splash drm.debug=4 intel_iommu=off
> i915.modeset=1 i915.i915_enable_fbc=1 i915.lvds_downclock=1
> i915.i915_enable_rc6=1 pcie_aspm=force"

Something worth mentioning is that the combination of pcie_aspm=force
and intel_iommu=off results in i915.modeset=0, with this combination,
I have to specify i915.modeset=1 to get hardware acceleration.

However, only specifying i915.i915_enable_rc6=1 and intel_iommu=off
keeps modeset=1.

Also I can confirm RC6 and iommu off still causes unexpected
shutdowns, even when booting without FBC, LVDS downclock and
pcie_aspm=force.