rd.zdev=no-auto - Override initial device availability for DPM mode

Device exclusion list

As a default for Linux in a DPM partition, auto-configuration data overrides device exclusion through cio_ignore. With rd.zdev=no-auto, the auto-configuration data is ignored and the exclusion list is enforced unchanged.

For more information about auto-configuration data, see Device auto-configuration for Linux in LPAR mode. For cio_ignore, see cio_ignore - Manage the I/O exclusion list.

PCIe or cryptographic devices

With the s390-utils package installed, the initial online status of PCIe devices and cryptographic devices for Linux in a DPM partition is online. Likewise, these devices are online after a reboot even if they were explicitly set offline before the reboot.

Using rd.zdev=no-auto, the initial online status of PCIe devices and cryptographic devices depends on defaults of your hardware and firmware levels. The online status of these devices on a running Linux instance is then preserved across reboots.

Linux in traditional LPAR mode

The rd.zdev=no-auto parameter does not affect Linux in traditional LPAR mode. After a reboot in this environment, the cio_ignore exclusion list is always enforced, and PCIe and cryptographic devices preserve their online status. The initial online status of a PCIe or cryptographic device depends on its hardware definition.