[Intel-gfx] [PATCH v2] drm/i915: gen4: work around hang during hibernation

[Jani Nikula]

On Mon, 02 Mar 2015, Bjørn Mork <bjorn at mork.no> wrote:
> Jani Nikula <jani.nikula at intel.com> writes:
>
>> On Mon, 02 Mar 2015, Imre Deak <imre.deak at intel.com> wrote:
>>> Bjørn reported that his machine hang during hibernation and eventually
>>> bisected the problem to the following commit:
>>>
>>> commit da2bc1b9db3351addd293e5b82757efe1f77ed1d
>>> Author: Imre Deak <imre.deak at intel.com>
>>> Date:   Thu Oct 23 19:23:26 2014 +0300
>>>
>>>     drm/i915: add poweroff_late handler
>>>
>>> The problem seems to be that after the kernel puts the device into D3
>>> the BIOS still tries to access it, or otherwise assumes that it's in D0.
>>> This is clearly bogus, since ACPI mandates that devices are put into D3
>>> by the OSPM if they are not wake-up sources. In the future we want to
>>> unify more of the driver's runtime and system suspend paths, for example
>>> by skipping all the system suspend/hibernation hooks if the device is
>>> runtime suspended already. Accordingly for all other platforms the goal
>>> is still to properly power down the device during hibernation.
>>>
>>> v2:
>>> - Another GEN4 Lenovo laptop had the same issue, while platforms from
>>>   other vendors (including mobile and desktop, GEN4 and non-GEN4) seem
>>>   to work fine. Based on this apply the workaround on all GEN4 Lenovo
>>>   platforms.
>>> - add code comment about failing platforms (Ville)
>>>
>>> Reference: http://lists.freedesktop.org/archives/intel-gfx/2015-February/060633.html
>>> Reported-and-bisected-by: Bjørn Mork <bjorn at mork.no>
>>> Signed-off-by: Imre Deak <imre.deak at intel.com>
>>
>> Bjørn, I would really appreciate your Tested-by on this patch before I
>> queue it for v4.0 and cc: stable for v3.19.
>
> No problem. This version still works fine for me.  Feel free to add
>
> Tested-by: Bjørn Mork <bjorn at mork.no>

Pushed to drm-intel-fixes with Daniel's IRC ack. Thanks for the patch
and testing.

BR,
Jani.


>
>
>
> Bjørn

-- 
Jani Nikula, Intel Open Source Technology Center