Installation guide

Release Notes

5. Kernel-Related Notes

5.1. All Architectures

• relayfs previously had a buffer size limit of 64MB. In this update, the limitation of the memory

allocated to relayfs for on-memory buffers has been increased to 4095MB. This allows SystemTap

and other tracing tools that utilize relayfs the ability to trace more events.

• The driver for Dell Remote Access Controller 4 (DRAC4) was not present. Consequently,

any virtual devices provided by the DRAC4 were not being detected by the kernel. In this update,

the pata_sil680 kernel module that provides the appropriate driver has been added, which resolves

this issue.

• The message buffers for the relay interface were only allocated for online CPUs when

relay_open() was called. Consequently, if an off-line CPU was turned on after relay_open()

was called, a kernel panic would occur. In this update, a new message buffer is allocated

dynamically if any new CPUs are added.

• The driver for 8250 based serial ports has been updated to add support for DSR/DTR hardware flow

control.

• Support for Dell Wireless Wide Area Network (WWAN) cards has been added to the kernel. Devices

that are now supported are:

• Dell Wireless 5700 Mobile Broadband CDMA/EVDO Mini-Card

• Dell Wireless 5500 Mobile Broadband HSDPA Mini-Card

• Dell Wireless 5505 Mobile Broadband HSDPA Mini-Card

• Dell Wireless 5700 Mobile Broadband CDMA/EVDO ExpressCard

• Dell Wireless 5510 Mobile Broadband HSDPA ExpressCard

• Dell Wireless 5700 Mobile Broadband CDMA/EVDO Mini-Card

• Dell Wireless 5720

• Dell Wireless HSDPA 5520

• Dell Wireless 5520 Voda I Mobile Broadband (3G HSDPA) Mini-Card

• the thinkpad_acpi kernel module has been updated to provide enhanced support for newer

Thinkpad models.

• The soft lockup detector can now be configured to trigger a kernel panic instead of a warning

message. This makes it possible for users to generate and analyze a crash dump during a soft

lockup for forensic purposes.

To configure the soft lockup detector to generate a panic, set the kernel parameter soft_lockup

to 1. This parameter is set to 0 by default.