On Fri, 30 Mar 2012, Aaron Lu wrote: > > > For the ODD to be put into suspend state, the conditions should be: > > > 1 tray closed > > > 2 no media inside > > > I think we missed the condition 1 check now. > > > > > > And if we follow the two conditions, the events can be safely ignored. > > > > No, they can't. Otherwise the device won't power back up when the user > > inserts a new disc. > > > > The ODD is put to zero power state, so it can't react to the eject > button without being powered up back first ;-) > On current implementation, ACPI is used to power back up the ODD like this: > 1 User press the eject button; > 2 A gpe event fired, and ACPI interrupt, and the corresponding gpe > handler runs and the ODD's ACPI handle is notified about DEVICE_WAKE_UP; > 3 In ODD's acpi notify handler, we power back up it by scsi_autopm_get_device. > This is handled in the following Lin Ming's patch: > [PATCH v3 2/7] libata-acpi: add ata port runtime D3Cold support I see. Then you are right; it's not necessary to check for events while the drive is at zero power. > When the ODD is put to zero power state, it will not be able to handle > commands like CDROMEJECT. We have to power it up first and then handle > the ioctl request. Currently, we only power back up the ODD when user > press the eject button as explained above. Then you may want to avoid going to zero-power while a program is holding the device file open. After all, the program might issue a CDROMEJECT ioctl. 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
