# HG changeset patch
# User Paul Boddie <paul@boddie.org.uk>
# Date 1495058020 -7200
# Node ID 3c8c93365e4733bbed3ded57d9e265f2e69aecfb
# Parent  2e365a839bc721bbc38c263a41cfacc49c11b430
Added missing operations to enable and disable the line channel.

diff -r 2e365a839bc7 -r 3c8c93365e47 vga.S
--- a/vga.S	Wed May 17 22:58:44 2017 +0200
+++ b/vga.S	Wed May 17 23:53:40 2017 +0200
@@ -439,10 +439,12 @@
 	occurs:
 	DCHxECON<15:8> = CHSIRQ<7:0> = timer 2 interrupt
 	DCHxECON<4> = SIRQEN = 1
+
+	For now, however, prevent initiation by not setting SIRQEN.
 	*/
 
 	la $v0, DCH0ECON
-	li $v1, (9 << 8) | (1 << 4)
+	li $v1, (9 << 8)
 	sw $v1, 0($v0)
 
 	/*
@@ -770,6 +772,12 @@
 
 	move $s2, $s3
 
+	/* Enable the line channel. */
+
+	la $v0, DCH0ECON
+	li $v1, (1 << 4)
+	sw $v1, SET($v0)
+
 _vbp_active_ret:
 	jr $ra
 	nop
@@ -789,6 +797,12 @@
 
 	la $s1, vfp_active
 
+	/* Disable the line channel. */
+
+	la $v0, DCH0ECON
+	li $v1, (1 << 4)
+	sw $v1, CLR($v0)
+
 _visible_active_ret:
 	jr $ra
 	nop