Red Hat ENTERPRISE LINUX 5.5 - TECHNICAL NOTES Manual page 112

Chapter 1. Package Updates
• Include core WMI support and Dell-WMI driver.
• [kabi] Add scsi_nl_{send_vendor_msg,{add,remove}_driver}.
• Enable ACPI 4.0 power metering.
• Add AER software error injection support.
• Add support for Syleus chip to fschmd driver.
• Implement support for DS8000 volumes.
• Support Lexar ExpressCard.
• Disable ARB_DISABLE on platforms where it is not needed.
ARB_DISABLE is a NOP on all of the recent Intel platforms. For such platforms, this update reduces
contention on the c3_lock by skipping the fake ARB_DISABLE.
This lock is held on each deep C-state entry and exit and with 16, 32, and 64 logical CPUs in NHM
EP, NHM EX platforms, this contention can become significant. Specifically on distributions that do
not have tickless feature and where all CPUs may wake up around the same time.
• Add zfcp parameter to dynamically adjust scsi_queue_depth size.
• Add HP ipmi message handling to Red Hat Enterprise Linux 5.
• Backport CONFIG_DETECT_HUNG_TASK to Red Hat Enterprise Linux 5.
In some circumstances, tasks in the kernel may permanently enter the uninterruptible sleep state
(D-State), making the system impossible to shut down. This update adds the Detect Hung Task
kernel thread, providing the ability to detect tasks permanently stuck in the D-State.
This new feature is controlled by the "CONFIG_DETECT_HUNG_TASK=" kernel flag. When set
to "y", tasks stuck in the D-State are detected; when set to "n" it is off. The default value for the
"CONFIG_DETECT_HUNG_TASK" flag is "y".
Additionally, the "CONFIG_BOOTPARAM_HUNG_TASK_PANIC" flag has been added. When set to
"y", a kernel panic is triggered when a task stuck in the D-State is detected. The default value for the
"CONFIG_BOOTPARAM_HUNG_TASK_PANIC" flag is "n".
• Add ability to access Nehalem uncore configuration space.
Systems that don't use MMCONFIG have trouble when allocating resources by using a legacy PCI
probe. As a result, the machine will hang during boot if the Disk PCI device is not properly initialized.
This update reverts a patch that improves the PCI ID detection in order to detect the new PCI
devices found on Nehalem machines. Consequently, the kernel will not hang on such machines. A
different patch will be needed, however, when adding any driver that needs to see the non-core set
of PCI devices on Nehalem.
• When booted with P-state limit, limit can never be increased
• Add do_settimeofday and __user_walk_fd
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