Re: [linux-fbdev] [PATCH] mdacon SMP fix

From: James Simmons (jsimmons@suse.com)
Date: Tue Oct 17 2000 - 01:05:22 EST


> Hi James,
>
> I think you missed to remove one restore_flags().....
> (There could be more, I only looked shortly at your patch)

Yeap. I didn't remove the restore_flag calls. Fixed now. Here is the
correct patch. I tested to see if it compiles against a test-9 kernel.
It does. That is the problem with fixing code that you don't have the
hardware for. You can't find those stupid mistakes before you post a
possible patch :-( It is next to impossible to find a MDA card. *shameless
plug *

--- mdacon.c.orig Wed Oct 11 18:09:01 2000
+++ mdacon.c Mon Oct 16 23:03:26 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
  */
 
@@ -110,39 +111,38 @@
 {
         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);
 
- restore_flags(flags);
+ spin_unlock_irqrestore(&mda_lock, flags);
 }
 
 static int test_mda_b(unsigned char val, unsigned char reg)
 {
         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;
 }
 

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