[linux-fbdev] [PATCH] mdacon SMP fix

[James Simmons]

ANyone with a MDA card on a SMP or even UP machione please test this
patch. This patch should fix any SMP deadlocks that could happen with 
a MDA card. Thank you.

--- mdacon.c.orig       Wed Oct 11 18:09:01 2000
+++ mdacon.c    Wed Oct 11 18:14:18 2000
@@ -37,6 +37,7 @@
 #include <linux/vt_kern.h>
 #include <linux/vt_buffer.h>
 #include <linux/selection.h>
+#include <linux/spinlock.h>
 #include <linux/ioport.h>
 #include <linux/delay.h>
 #include <linux/init.h>
@@ -44,6 +45,7 @@
 #include <asm/io.h>
 #include <asm/vga.h>
 
+static spinlock_t mda_lock = SPIN_LOCK_UNLOCKED;
 
 /* description of the hardware layout */
 
@@ -80,7 +82,6 @@
 MODULE_PARM(mda_last_vc,  "1-255i");
 #endif
 
-
 /* MDA register values
  */
 
@@ -110,23 +111,24 @@
 {
        unsigned long flags;
 
-       save_flags(flags); cli();
+       spin_lock_irqsave(&mda_lock, flags);    
 
        outb_p(reg, mda_index_port); 
        outb_p(val, mda_value_port);
 
-       restore_flags(flags);
+       spin_unlock_irqrestore(&mda_lock, flags);
 }
 
 static void write_mda_w(unsigned int val, unsigned char reg)
 {
        unsigned long flags;
 
-       save_flags(flags); cli();
+       spin_lock_irqsave(&mda_lock, flags);
 
        outb_p(reg,   mda_index_port); outb_p(val >> 8,   mda_value_port);
        outb_p(reg+1, mda_index_port); outb_p(val & 0xff, mda_value_port);
 
+       spin_unlock_irqrestore(&mda_lock, flags);
        restore_flags(flags);
 }
 
@@ -134,15 +136,14 @@
 {
        unsigned long flags;
 
-       save_flags(flags); cli();
+       spin_lock_irqsave(&mda_lock, flags);
 
        outb_p(reg, mda_index_port); 
        outb  (val, mda_value_port);
 
        udelay(20); val = (inb_p(mda_value_port) == val);
 
-       restore_flags(flags);
-
+       spin_unlock_irqrestore(&mda_lock, flags);
        return val;
 }