FDC motor left on

[Richard B. Johnson]

In linux-2.4.22 and earlier, if there is no FDC driver installed,
the FDC motor may continue to run after boot if the motor was
started as part of the BIOS boot sequence.
This patch turns OFF the motor once Linux gets control.


--- linux-2.4.22/arch/i386/boot/setup.S.orig	Fri Aug  2 20:39:42 2002
+++ linux-2.4.22/arch/i386/boot/setup.S	Fri Oct  3 11:50:43 2003
@@ -59,6 +59,8 @@
 #define SIG1	0xAA55
 #define SIG2	0x5A5A

+FDC_MOTOR = 0x3f2
+FDC_MOTON = 0x10
 INITSEG  = DEF_INITSEG		# 0x9000, we move boot here, out of the way
 SYSSEG   = DEF_SYSSEG		# 0x1000, system loaded at 0x10000 (65536).
 SETUPSEG = DEF_SETUPSEG		# 0x9020, this is the current segment
@@ -776,6 +778,12 @@

 	movb	$0xFB, %al			# mask all irq's but irq2 which
 	outb	%al, $0x21			# is cascaded
+
+	movl	$FDC_MOTOR, %edx		# FDC motor control
+	inb	%dx, %al			# Get what's there
+	andb	$~FDC_MOTON, %al		# Reset motor bit
+	outb	%al, %dx			# Turn OFF motor
+

 # Well, that certainly wasn't fun :-(. Hopefully it works, and we don't
 # need no steenking BIOS anyway (except for the initial loading :-).



Cheers,
Dick Johnson
Penguin : Linux version 2.4.22 on an i686 machine (797.90 BogoMips).
            Note 96.31% of all statistics are fiction.


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