x86: various changes and cleanups to in_p/out_p delay details

various changes to the in_p/out_p delay details:

- add the io_delay=none method
- make each method selectable from the kernel config
- simplify the delay code a bit by getting rid of an indirect function call
- add the /proc/sys/kernel/io_delay_type sysctl
- change 'io_delay=standard|alternate' to io_delay=0x80 and io_delay=0xed
- make the io delay config not depend on CONFIG_DEBUG_KERNEL

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Tested-by: "David P. Reed" <dpreed@reed.com>

1 files changed, 7 insertions, 5 deletions

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 9e6056058425..b427b7c0e5d0 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -795,12 +795,14 @@ and is between 256 and 4096 characters. It is defined in the file
                         then look in the higher range.
 
         io_delay=       [X86-32,X86-64] I/O delay method
-                standard
-                        Standard port 0x80 delay
-                alternate
-                        Alternate port 0xed delay
+                0x80
+                        Standard port 0x80 based delay
+                0xed
+                        Alternate port 0xed based delay (needed on some systems)
                 udelay
-                        Simple two microsecond delay
+                        Simple two microseconds delay
+                none
+                        No delay
 
         io7=            [HW] IO7 for Marvel based alpha systems
                         See comment before marvel_specify_io7 in