On Tue, Apr 25, 2017 at 9:28 AM, Adrian Hunter <adrian.hunter@xxxxxxxxx> wrote:
> On 25/04/17 00:52, Rafael J. Wysocki wrote:
>> On Fri, Apr 21, 2017 at 12:08 PM, Adrian Hunter <adrian.hunter@xxxxxxxxx> wrote:
>>> SDIO reset interferes with a SDIO function driver's restore from
>>> hibernation. Set MMC_CAP2_NO_SDIO_RESET if a child node has _S4W method
>>> which indicates a capability to wake from S4 (hibernate).
>>>
>>> Signed-off-by: Adrian Hunter <adrian.hunter@xxxxxxxxx>
>>> ---
>>> drivers/mmc/host/sdhci-acpi.c | 17 ++++++++++++++++-
>>> 1 file changed, 16 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/drivers/mmc/host/sdhci-acpi.c b/drivers/mmc/host/sdhci-acpi.c
>>> index c6a9a1bfaa22..e053a45db6b1 100644
>>> --- a/drivers/mmc/host/sdhci-acpi.c
>>> +++ b/drivers/mmc/host/sdhci-acpi.c
>>> @@ -374,6 +374,14 @@ static const struct sdhci_acpi_slot *sdhci_acpi_get_slot(const char *hid,
>>> return NULL;
>>> }
>>>
>>> +static bool sdhci_acpi_child_has_s4w(struct acpi_device *child)
>>> +{
>>> + acpi_handle handle = child->handle;
>>> + unsigned long long ret;
>>> +
>>> + return ACPI_SUCCESS(acpi_evaluate_integer(handle, "_S4W", NULL, &ret));
>>
>> First off, there is acpi_has_method().
>>
>> Second, checking child->wakeup.sleep_state is a better indicator of S4
>> wakeup support.
>
> So, like this?
>
> child->wakeup.sleep_state >= ACPI_STATE_S4
>
> That comes just from _PRW right?
It may be fixed up if the power resources in there don't match what
_PRW itself returns, but generally yes.
In any case _S4W is optional even for devices that can wake up from S4 IIRC.
Thanks,
Rafael
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