Red Hat Bugzilla – Bug 157586
ES7000 systems won't boot with large configuration
Last modified: 2007-11-30 17:07:18 EST
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Description of problem:
ES7000 systems won't boot with large configuration, because of legacy code that enforces I/O APIC ID's to be unique system wide. Unique I/O APIC ID only makes sense with Intel processors older than Xeons, that were utilizing serial APIC bus for interrupt delivery. With front side bus architecture, where I/O APIC IDs are not used, this check is obsolete, and also harmful when tries to re-assign the IDs on systems like ES7000, that employ Intel's P64H2 chipset. The IDs of its I/O APICs are only 4 bit wide and cannot be assigned unique numbers.
Recently, this issue was discussed on LK, and two patches dealing with it were submitted and accepted in the main line, see http://kernel.org/pub/linux/kernel/people/akpm/patches/2.6/2.6.12-rc4/2.6.12-rc4-mm1/broken-out/:
remove-unique-apic-io-apic-id-check.patch - for x86_64
The patches were tested on generic Intel boxes and ES7000, both IA-32 and x86_64.
Since the patches are critical for our release, and appear to be low risk, we would like them to be included it in your kernel for the next update.
Version-Release number of selected component (if applicable):
Steps to Reproduce:
1. Boot x86_64 ES7000 that was configured with two cells
2. Watch the screen hang after the initial message
Actual Results: We used ITP to see the actual problem, or it can also be done with early_printk configured. The system paniced with error message "IOAPIC: Unable change apic_id!"
Expected Results: The boot should've proceeded normally.
An advisory has been issued which should help the problem
described in this bug report. This report is therefore being
closed with a resolution of ERRATA. For more information
on the solution and/or where to find the updated files,
please follow the link below. You may reopen this bug report
if the solution does not work for you.