Allow number of IDE interfaces to be selected (X86)

A small patch I done to allow X86 users to select the max number of IDE interfaces they have - this eliminates the need for passing idex=noprobe on the command line and/or stops the needless probes at boot on non-existant IDE interfaces.

I have done this as I assume the majority of X86 users will only have 2 IDE interfaces, and therefore it allows the option to specify this.

ALPHA and SUPERH users need to select this to continue as per the way it works for them.

For X86 people, not selecting this allows the kernel to use the defaults 'as was'.

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 drivers/ide/Kconfig    |   17 ++++++++++++++++-
 include/asm-i386/ide.h |    4 ++++
 2 files changed, 20 insertions(+), 1 deletion(-)

--- linux-2.6.12n/include/asm-i386/ide.h 2005-06-17 20:48:29.000000000
+0100
+++ linux-2.6.12/include/asm-i386/ide.h 2005-06-25 14:13:43.000000000 +0100 @@ -16,11 +16,15 @@
#include <linux/config.h>

#ifndef MAX_HWIFS
+#ifndef CONFIG_IDE_HWIFS_NUM

 # ifdef CONFIG_BLK_DEV_IDEPCI
 #define MAX_HWIFS      10
 # else
 #define MAX_HWIFS      6
 # endif
+#else
+#define MAX_HWIFS       CONFIG_IDE_MAX_HWIFS
+#endif
 #endif

#define IDE_ARCH_OBSOLETE_DEFAULTS

@@ -52,14 +52,29 @@
 
 if IDE
 
+config IDE_HWIFS_NUM
+        bool "Specify the number of IDE Interfaces"
+       depends on (ALPHA || SUPERH || X86)
+        default n
+       help
+
+         ALPHA and SUPERH say 'y' here.
+
+         X86 say 'y' to this if you wish to specify the number of IDE
+         interfaces on your system.  If unsure, say 'n' to use
+         the kernel default options (6 or 10).
+
 config IDE_MAX_HWIFS
        int "Max IDE interfaces"
-       depends on ALPHA || SUPERH
+       depends on IDE_HWIFS_NUM
        default 4
        help
          This is the maximum number of IDE hardware interfaces that will
          be supported by the driver. Make sure it is at least as high as
          the number of IDE interfaces in your system.
+
+         On X86 architecture default is (6 or 10) IDE interfaces if this
+         is not used (IDE_HWIFS_NUM = n)
 
 config BLK_DEV_IDE
        tristate "Enhanced IDE/MFM/RLL disk/cdrom/tape/floppy support"

Nick

"When you're chewing on life's gristle,
Don't grumble, Give a whistle..."

The needless probe cases patch went into -mm already. Also your change doesn't eliminate the need for noprobe in cases where its not the first or second interface in order.

The assumption most x86 users will only have two IDE interfaces is also generally wrong today, although they may fall under the SATA driver on newer boards.

I don't think this patch should go in - the one real reason for having it in embedded boxes was saving memory. The right fix for that is already something Bartlomiej has talked about fixing - the static allocation of the ide_hwifs array itself.

Alan

OK :-).

But I learnt a lot here on the kernel.

Also found not to cut 'n' paste from nano in X. It doesn't perserve tabs... so the patch was bum anyway. I only found out it was fubar when I was looking at what Matt done to get the struct sizes on different vmlinuz builds, and cut and paste back into a file from the mail.

But here is the results anyway using my .config but with the option off and on:

Orig (off):

bash-2.05b# nm -t d -rS --size-sort linux-2.6.12orig/vmlinux | grep hwifs 0000003225966208 0000000000014080 B ide_hwifs

With the IDE selection option (but not EMBEDDED) with 2 IDE interfaces selected (on with 2):

bash-2.05b# nm -t d -rS --size-sort linux-2.6.12/vmlinux | grep hwifs 0000003225974400 0000000000002816 B ide_hwifs

Nick

"When you're chewing on life's gristle,
Don't grumble, Give a whistle..."