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, 3 insertions, 7 deletions

diff --git a/include/asm-x86/io_32.h b/include/asm-x86/io_32.h
index a8d25c38b91c..2a04bd17eac5 100644
--- a/include/asm-x86/io_32.h
+++ b/include/asm-x86/io_32.h
@@ -250,15 +250,11 @@ static inline void flush_write_buffers(void)
 
 #endif /* __KERNEL__ */
 
-#ifndef CONFIG_UDELAY_IO_DELAY
-extern void io_delay_init(void);
-#else
-static inline void io_delay_init(void)
-{
-}
-#endif
 extern void native_io_delay(void);
 
+extern int io_delay_type;
+extern void io_delay_init(void);
+
 #if defined(CONFIG_PARAVIRT)
 #include <asm/paravirt.h>
 #else