Thanks for the feedback, I've taken things back to the drawing board in lieu of these issues and will be resubmitting once I have a patch that fits better into the formal power management architecture. Would you like to be CC'ed? Todd Brandt Linux Kernel Developer OTC, Hillsboro OR https://opensource.intel.com/linux-wiki/ToddBrandt ________________________________________ From: Alan Stern [stern@xxxxxxxxxxxxxxxxxxx] Sent: Friday, May 17, 2013 12:44 PM To: Brandt, Todd E Cc: linux-ide@xxxxxxxxxxxxxxx; linux-scsi@xxxxxxxxxxxxxxx; linux-pm@xxxxxxxxxxxxxxx; Jeff Garzik; Jens Axboe; Greg Kroah-Hartman; Wysocki, Rafael J; Arjan van de Ven Subject: Re: [PATCH v2 2/2] Adds new device resume mode in PM core, async plus non-blocking On Fri, 17 May 2013, Brandt, Todd E wrote: > Updates the drivers/base/power subsystem to allow any devices which > have registred as asynchronous and who have not registered "complete" > callbacks to be non-blocking. i.e system resume can finish and return > control to the user while these devices continue resuming. This does not sound like a good idea. The presence or absence of a "complete" callback has nothing to do with whether or not system resume can finish before the device is ready. It is more closely related to whether the device's driver can register hot-plugged children below the device or needs to perform other actions after the children have been resumed. The whole approach seems wrong -- it violates the implicit agreement that the kernel will not try to perform I/O through a device that isn't at full power. A better approach would be to modify the SCSI disk driver to carry out the spin-up operation asynchronously with respect to the resume callback. Then the disk could be reported as back to full power while the spin-up is taking place. Alan Stern -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
