HI, > 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. I would expect that this capability controls sending SSU 4, but it only controls the sysfs entry?
> > It is assumed that UFS devices with wspecversion >= 0x310 support > DeepSleep. > > The UFS specification says to set the IMMED (immediate) flag for the > Start/Stop Unit command when entering DeepSleep. However some UFS > devices object to that, which is addressed in a subsequent patch. After failing to understand what the proper behavior should be with respect of the IMMED bit, Although I read the applicable section few time, I gave up and consult our system guy, Which is our jedec representative. This is his answer: "... In order to avoid uncertainty - the host need to set IMMED bit to '0' (this is explicitly specified by the standard). The device responds only after it switches to Pre-DeepSleep state. The host then switch to H8 and this would trigger the device to transition to DeepSleep state. ..." So maybe the 2nd patch isn't really needed. Thanks, Avri
