Re: [PATCH] drm/i915: make system freeze support depend on CONFIG_ACPI_SLEEP

["Rafael J. Wysocki" <rafael.j.wysocki@intel.com>]

On 6/24/2014 5:12 PM, Imre Deak wrote:
> On Tue, 2014-06-24 at 17:53 +0300, Jani Nikula wrote:
>> On Tue, 24 Jun 2014, Imre Deak <imre.deak@intel.com> wrote:
>>> On Tue, 2014-06-24 at 16:54 +0300, Jani Nikula wrote:
>>>> On Mon, 23 Jun 2014, Imre Deak <imre.deak@intel.com> wrote:
>>>>> To achieve further power savings during system freeze (aka connected
>>>>> standby, or s0ix) we have to send a PCI_D1 opregion notification. As
>>>>> the information about the state we're entering (system freeze,
>>>>> suspend to ram or suspend to disk) is only available through the ACPI
>>>>> subsystem, make this support depend on the relevant kconfig option.
>>>>> Things will still work if this option isn't set, albeit with less than
>>>>> optimial power saving.
>>>>>
>>>>> This also fixes a compile breakage when the option is not set introduced
>>>>> in
>>>>>
>>>>> commit e5747e3adcd67ae27105003ec99fb58cba180105
>>>>> Author: Jesse Barnes <jbarnes@virtuousgeek.org>
>>>>> Date:   Thu Jun 12 08:35:47 2014 -0700
>>>>>
>>>>>      drm/i915: send proper opregion notifications on suspend/resume
>>>>>
>>>>> Reported-by: Randy Dunlap <rdunlap@infradead.org>
>>>>> Signed-off-by: Imre Deak <imre.deak@intel.com>
>>>>> ---
>>>>>   drivers/gpu/drm/i915/i915_drv.c | 7 ++++---
>>>>>   1 file changed, 4 insertions(+), 3 deletions(-)
>>>>>
>>>>> diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
>>>>> index 7ae4e2a..43dc8f7 100644
>>>>> --- a/drivers/gpu/drm/i915/i915_drv.c
>>>>> +++ b/drivers/gpu/drm/i915/i915_drv.c
>>>>> @@ -544,10 +544,11 @@ static int i915_drm_freeze(struct drm_device *dev)
>>>>>   
>>>>>   	i915_save_state(dev);
>>>>>   
>>>>> -	if (acpi_target_system_state() >= ACPI_STATE_S3)
>>>>> -		opregion_target_state = PCI_D3cold;
>>>>> -	else
>>>>> +	opregion_target_state = PCI_D3cold;
>>>>> +#if IS_ENABLED(CONFIG_ACPI_SLEEP)
>>>> Maybe this should just check for CONFIG_ACPI?
>>> I wanted to send the PCI_D1 signal only if we are sure that the target
>>> sleep state is S0ix (or S1/2) and fall back to the old behavior to send
>>> PCI_D3cold in all other cases.
>>>
>>> But you are right, it would make much sense if CONFIG_ACPI_SLEEP=n the
>>> target state would be always S0ix. Rafael could you confirm this?

The target state should be S0 for CONFIG_ACPI_SLEEP unset.

>> intel_opregion_notify_adapter() is a NOP for CONFIG_ACPI=n anyway.
> Ok, but the question for me is what's the target sleep state in case of
> CONFIG_ACPI=y and CONFIG_ACPI_SLEEP=n.
>
>>   And AFAICT CONFIG_ACPI=y && CONFIG_ACPI_SLEEP=n is broken.

Broken how?

> But it seems like a valid configuration. So it needs to be fixed
> separately.

It is a valid configuration.

Rafael