Kernel 3.19

If you download any software from this web site please be aware of the Warranty Disclaimer and Limitation of Liabilities.

Kernel downloads for the "Development stream"

Download Description
upstream kernel 3.19 kernel 3.19 - upstream with feature descriptions.
linux-3.19-s390-message-catalog.tar.gz / MD5 "Development Stream" kernel 3.19 - message-catalog (optional)

2015-06-01: kernel 3.19 - upstream (feature description)

To download the linux-3.19.tar.gz visit:

The upstream kernel 3.19 contains the following functionality developed by the Linux on z Systems development team:

Provides two new system calls allowing user space applications to access PCI MMIO pages
On z Systems, access to MMIO memory requires privileged instructions. This prevents applications to use arbitrary memory access instructions to use MMIO as on other platforms. Instead, this feature introduces two new system calls, s390_pci_mmio_read and s390_pci_mmio_write, allowing MMIO access through the use of privileged instructions in the kernel. Applications using MMIO need to be adapted to invoke these system calls to initiate MMIO operations.
This feature can only be used on z Systems where PCI hardware is supported and only be used on LPAR.

Performance improvements to the Flash Express device driver
This item modifies the Flash Express device driver to support more outstanding I/Os to Flash Express hardware at a time. As a result, the maximum achievable number of Linux I/Os per second should be closer to the theoretical Flash Express hardware limits for applications that generate I/O workloads with corresponding queue depths.
This function is supported on LPAR only and where Flash Express is attached.
For documentation see Device Drivers, Features, and Commands (with kernel 4.0), Chapter 12 'Storage-class memory device driver supporting Flash Express'.

Improve zfcp auto port scan resiliency
Improve the Fibre Channel port scan behaviour of the zfcp lldd, particularly in big virtual server environments, by the introduction of a rate limit to amend frequency issues, and the introduction of a short random backoff to amend simultaneity issues.
For documentation see Device Drivers, Features, and Commands (with kernel 4.0), Chapter 11. 'SCSI-over-Fibre Channel' Section 'Controlling automatic port scanning'.

Reintroduce selected zfcp unit sysfs attributes for scsi devices
With this feature, you can trigger manual LUN recovery and export debug data for zfcp-attached SCSI devices that are attached by automatic LUN scan.
For documentation see Device Drivers, Features, and Commands (with kernel 4.0), Chapter 'SCSI-over-Fibre Channel device driver', Sections 'Displaying information about SCSI devices' and 'Recovering failed SCSI devices'.

2015-06-01: "Development Stream" kernel 3.19 message catalog (feature - optional patch)

linux-3.19-s390-message-catalog.tar.gz / MD5 ... recommended (2015-06-01)

This patch contains:

Kernel message catalog.
Add support for automatic message tags to the printk macro families dev_xyz and pr_xyz. The message tag consists of a component name and a 24 bit hash of the message text. For each message that is documented in the included kernel message catalog a man page can be created with a script (which is included in the patch). The generated man pages contain explanatory text that is intended to help understand the messages.

Note that only s390 specific messages are prepared appropriately and included in the generated message catalog.

This patch is optional as it is very unlikely to be accepted in upstream kernel, but is recommended for all distributions which are built based on the 'Development stream'.