[PATCH] kdump documentation update to introduce use of irqpoll

o Specify "irqpoll" command line option which loading second kernel. This
  helps in reducing driver initialization failures in second kernel due
  to shared interrupts.
o Enabled LAPIC/IOAPIC support for UP kernels in second kernel. This reduces
  the chances of devices sharing the irq and hence reduces the chances of
  driver initialization failures in second kernel.
o Build a UP capture kernel and disabled SMP support.

Signed-off-by: Vivek Goyal <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

Documentation/kdump/kdump.txt

@@ -66,33 +66,39 @@ SETUP
 	CONFIG_PHYSICAL_START=0x1000000
    c) Enable "/proc/vmcore support" (Optional, in Pseudo filesystems).
 	CONFIG_PROC_VMCORE=y
-
-  Note: Options a) and b) depend upon "Configure standard kernel features
-	(for small systems)" (under General setup).
-	Option a) also depends on CONFIG_HIGHMEM (under Processor
+   d) Disable SMP support and build a UP kernel (Until it is fixed).
+   	CONFIG_SMP=n
+   e) Enable "Local APIC support on uniprocessors".
+   	CONFIG_X86_UP_APIC=y
+   f) Enable "IO-APIC support on uniprocessors"
+   	CONFIG_X86_UP_IOAPIC=y
+
+  Note:   i) Options a) and b) depend upon "Configure standard kernel features
+	     (for small systems)" (under General setup).
+	 ii) Option a) also depends on CONFIG_HIGHMEM (under Processor
 		type and features).
-	Both option a) and b) are under "Processor type and features".
+	iii) Both option a) and b) are under "Processor type and features".
 
 3) Boot into the first kernel. You are now ready to try out kexec-based crash
    dumps.
 
 4) Load the second kernel to be booted using:
 
    kexec -p <second-kernel> --crash-dump --args-linux --append="root=<root-dev>
-   maxcpus=1 init 1"
+   init 1 irqpoll"
 
    Note: i) <second-kernel> has to be a vmlinux image. bzImage will not work,
 	    as of now.
 	ii) By default ELF headers are stored in ELF32 format (for i386). This
 	    is sufficient to represent the physical memory up to 4GB. To store
 	    headers in ELF64 format, specifiy "--elf64-core-headers" on the
 	    kexec command line additionally.
-       iii) For now (or until it is fixed), it's best to build the
-	    second-kernel without multi-processor support, i.e., make it
-	    a uniprocessor kernel.
+       iii) Specify "irqpoll" as command line parameter. This reduces driver
+            initialization failures in second kernel due to shared interrupts.
 
 5) System reboots into the second kernel when a panic occurs. A module can be
-   written to force the panic, for testing purposes.
+   written to force the panic or "ALT-SysRq-c" can be used initiate a crash
+   dump for testing purposes.
 
 6) Write out the dump file using
 
@@ -131,5 +137,5 @@ TODO
 CONTACT
 =======
 
-Hariprasad Nellitheertha - hari at in dot ibm dot com
 Vivek Goyal ([email protected])
+Maneesh Soni ([email protected])