Re: [PATCH] scsi: sr: use block layer runtime PM

[Aaron Lu <aaron.lu@intel.com>]

On 09/05/2013 10:25 PM, Alan Stern wrote:
> On Thu, 5 Sep 2013, Aaron Lu wrote:
> 
>> Migrate SCSI Optical Disk Drive(ODD) driver sr to make use of block
>> layer runtime PM. Accordingly, the SCSI bus layer runtime PM callback is
>> simplified as all SCSI devices that implement runtime PM are now request
>> based.
>>
>> Signed-off-by: Aaron Lu <aaron.lu@intel.com>
>> ---
>> Note that due to ODD will be polled every 2 seconds, for suspend to
>> actually happen, the autosuspend_delay can not be set to more than 2
>> seconds.
> 
> Or the polling delay must be increased.
> 
>> Also, make sure to use the util-linux utility of version 2.23.2 or later,
>> as there is a bug fix for eject command to correctly update the ODD's
>> locked state. If the fix is not applied, after the ODD is ejected with the
>> eject command, it will not be able to enter runtime suspend state any
>> more due to SCSI EH code will submit a lock door command for the ODD
>> right after its parent ATA port is runtime suspended.
>> https://git.kernel.org/cgit/utils/util-linux/util-linux.git/commit/?id=12272030e563201e0b06732d8a87d8cea7157a04
> 
> I think this patch will cause a compile warning if you have
> CONFIG_PM_RUNTIME set and CONFIG_PM_SLEEP disabled.  The
> scsi_dev_type_suspend and scsi_dev_type_resume routines will be defined
> but not used.

Oh, right, thanks for the remind. I'll move CONFIG_PM_SLEEP up to cover
scsi_dev_type_suspend/resume in v2.

> 
> Otherwise it seems okay.
>

Thanks,
Aaron