On 6/1/23 08:56, Kai-Heng Feng wrote:
During system resuming process, the resuming order is from top to down. Namely, the ATA host is resumed before disks connected to it. When an EH is scheduled while ATA host is resumed and disk device is still suspended, the device_lock hold by scsi_rescan_device() is never released so the dpm_resume() of the disk is blocked forerver, therefore the system can never be resumed back. That's because scsi_attach_vpd() is expecting the disk device is in operational state, as it doesn't work on suspended device. To avoid such deadlock, wait until the scsi device is fully resumed, before continuing the rescan process.
Why doesn't scsi_attach_vpd() support runtime power management? Calling scsi_attach_vpd() should result in a call of sdev_runtime_resume(), isn't it?
Thanks, Bart.
