On 27 October 2016 at 17:06, Thierry Escande
<thierry.escande@xxxxxxxxxxxxx> wrote:
> Hi Ulf,
>
> On 25/10/2016 12:03, Ulf Hansson wrote:
>>
>> On 3 October 2016 at 16:19, Thierry Escande
>> <thierry.escande@xxxxxxxxxxxxx> wrote:
>>>
>>> From: zhaojohn <john.zhao@xxxxxxxxx>
>>>
>>> Hynix eMMC devices sometimes take 50% longer to resume from sleep.
>>> Based on a recommendation from Hynix, send a Power-Off Notification
>>> before going to S3 to restore a resume time consistently within spec.
>>
>>
>> Could you also share what mmc controller and SoC you get this results
>> from?
>>
>> More precisely, are you using MMC_CAP_WAIT_WHILE_BUSY?
>
> This occurs on a braswell based chromebook, using the acpi sdhci controller.
> So yes, using MMC_CAP_WAIT_WHILE_BUSY.
>
> [...]
>>>
>>> diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
>>> index f2d185c..46a4562 100644
>>> --- a/drivers/mmc/core/mmc.c
>>> +++ b/drivers/mmc/core/mmc.c
>>> @@ -1925,8 +1925,14 @@ static int _mmc_suspend(struct mmc_host *host,
>>> bool is_suspend)
>>> if (mmc_can_poweroff_notify(host->card) &&
>>> ((host->caps2 & MMC_CAP2_FULL_PWR_CYCLE) || !is_suspend))
>>> err = mmc_poweroff_notify(host->card, notify_type);
>>> - else if (mmc_can_sleep(host->card))
>>> + else if (mmc_can_sleep(host->card)) {
>>> + if (host->card->quirks &
>>> MMC_QUIRK_NOTIFY_POWEROFF_ON_SLEEP) {
>>> + err = mmc_poweroff_notify(host->card,
>>> notify_type);
>>> + if (err)
>>> + goto out;
>>> + }
>>
>>
>> So, I am curious to know from a power management point of view; how
>> does the card behave comparing the sleep and power off notification
>> command?
>>
>> Is the card in a low power state after the power off notification has
>> been received? If so, did you manage to do some measurement for that
>> or perhaps the data-sheet tells about this? It would be interesting to
>> know if there were any differences between sleep and power off
>> notification in this regards.
>
> I do not have any clue about that. It appears only with Hynix emmc and the
> fix has been approved by Hynix engineers... It seems that if not powered
> off, the firmware does some garbage collection when resuming and it takes
> more time...
Okay, I see. So before I continue reviewing, can you please also tell
what regulators to the card that is being cut while powering off in
this path.
VMMC, VQMMC?
Kind regards
Uffe
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