Re: [PATCH V4 1/2] scsi: ufs: Add DeepSleep feature

From: Stanley Chu
Date: Wed Nov 04 2020 - 20:43:00 EST


On Tue, 2020-11-03 at 16:14 +0200, Adrian Hunter wrote:
> DeepSleep is a UFS v3.1 feature that achieves the lowest power consumption
> of the device, apart from power off.
>
> In DeepSleep mode, no commands are accepted, and the only way to exit is
> using a hardware reset or power cycle.
>
> This patch assumes that if a power cycle was an option, then power off
> would be preferable, so only exit via a hardware reset is supported.
>
> Drivers that wish to support DeepSleep need to set a new capability flag
> UFSHCD_CAP_DEEPSLEEP and provide a hardware reset via the existing
> ->device_reset() callback.
>
> It is assumed that UFS devices with wspecversion >= 0x310 support
> DeepSleep.
>
> Signed-off-by: Adrian Hunter <adrian.hunter@xxxxxxxxx>

Reviewed-by: Stanley Chu <stanley.chu@xxxxxxxxxxxx>