From ba9cc63b1ecb55c7fb843d9227cfaadfe7b7ed36 Mon Sep 17 00:00:00 2001
From: David du Colombier <0intro@gmail.com>
Date: Sat, 19 Nov 1994 00:00:00 +0000
Subject: [PATCH] Plan 9 from Bell Labs 1994-11-19

---
 pc/devastar.c | 29 +++++++++++++++++++----------
 pc/devvga.c   | 15 +++++++++------
 2 files changed, 28 insertions(+), 16 deletions(-)

diff --git a/pc/devastar.c b/pc/devastar.c
index 2fa4dafd52126004886c448fa490e3e855926bd7..d5fb69853349398245669a89a4db33895fb8f2f3 100644
--- a/pc/devastar.c
+++ b/pc/devastar.c
@@ -415,17 +415,21 @@ astarreset(void)
 			astar[nastar] = 0;
 			continue;
 		}
-		print("serial%d avanstar port %d addr %lux irq %d\n", i, a->port,
+		print("serial%d avanstar port 0x%lux addr %lux irq %d\n", i, a->port,
 			a->addr, a->irq);
 		nastar++;
 
+		/* disable ISA memory response */
+		c = inb(a->port+ISActl2);
+		outb(a->port+ISActl2, c & ~ISAmen);
+
+		/* download mode to turn off cpu */
 		c = inb(a->port+ISActl1);
 		outb(a->port+ISActl1, c & ~ISAnotdl);
 		a->memsize = Pramsize;
-
-		c = inb(a->port+ISActl2);
-		outb(a->port+ISActl2, c & ~ISAmen);
 		a->page = -1;
+
+		setvec(Int0vec + a->irq, astarintr, a);
 	}
 }
 
@@ -722,6 +726,7 @@ startcp(Astar *a)
 		error(Eio);
 
 	/* take board out of download mode and enable IRQ */
+print("out of download\n");
 	outb(a->port+ISActl1, ISAien|isairqcode[a->irq]|ISAnotdl);
 	a->memsize = a->ramsize;
 	setpage(a, 0);
@@ -731,6 +736,7 @@ startcp(Astar *a)
 		a->needpage = 1;
 
 	/* wait for control program to signal life */
+print("waiting for cp\n");
 	for(i = 0; i < 21; i++){
 		if(inb(a->port+ISActl1) & ISApr)
 			break;
@@ -745,6 +751,7 @@ startcp(Astar *a)
 		UNLOCKPAGE(a);
 		poperror();
 	}
+
 	LOCKPAGE(a, 0);
 	i = LEUS(a->gcb->type);
 	switch(i){
@@ -776,8 +783,12 @@ startcp(Astar *a)
 		}
 	}
 
+	/* enable control program interrupt generation */
+	a->gcb->cmd2 = LEUS(Gintack);
+
 	UNLOCKPAGE(a);
 	poperror();
+print("setting up channels\n");
 
 	/* setup the channels */
 	a->running = 1;
@@ -792,12 +803,6 @@ startcp(Astar *a)
 		ac->oq = qopen(4*1024, 0, astarkick, ac);
 		x += sz;
 	}
-
-	/* enable control program interrupt generation */
-	setvec(Int0vec + a->irq, astarintr, a);
-	LOCKPAGE(a, 0);
-	a->gcb->cmd2 = LEUS(Gintack);
-	UNLOCKPAGE(a);
 }
 
 static void
@@ -1293,6 +1298,10 @@ astarintr(Ureg *ur, void *arg)
 	lock(&a->pagelock);
 	if(a->needpage)
 		setpage(a, 0);
+	if(a->running == 0){
+		print("astar interrupt but cp not running\n");
+		return;
+	}
 
 	/* get causes */
 	invec = LEUS(xchgw(&a->gcb->inserv, 0));
diff --git a/pc/devvga.c b/pc/devvga.c
index aca088f8e81232429131dffa6ebb0b2459e366c0..08b4f2c3b4801ce96a78d9cff6e59fbada925eae 100644
--- a/pc/devvga.c
+++ b/pc/devvga.c
@@ -539,6 +539,7 @@ VGAmode mode13 =
 static void
 setmode(VGAmode *vga)
 {
+	uchar seq00, seq01;
 	int i;
 
 	/*
@@ -547,17 +548,19 @@ setmode(VGAmode *vga)
 	 * Load the generic VGA registers:
 	 *	misc;
 	 *	sequencer;
-	 *	take the sequencer out of reset;
+	 *	restore the sequencer reset state;
 	 *	take off write-protect on crt[0x00-0x07];
 	 *	crt;
 	 *	graphics;
 	 *	attribute;
-	 * Turn on the screen.
+	 * Restore the screen state.
 	 */
-	vgaxo(Seqx, 0x01, 0x21);
-
+	seq00 = vgaxi(Seqx, 0x00);
 	vgaxo(Seqx, 0x00, 0x00);
 
+	seq01 = vgaxi(Seqx, 0x01);
+	vgaxo(Seqx, 0x01, seq01|0x20);
+
 	vgao(MiscW, vga->misc);
 
 	for(i = 1; i < NSeqx; i++){
@@ -565,7 +568,7 @@ setmode(VGAmode *vga)
 			continue;
 		vgaxo(Seqx, i, vga->sequencer[i]);
 	}
-	vgaxo(Seqx, 0x00, 0x03);
+	vgaxo(Seqx, 0x00, seq00);
 
 	vgaxo(Crtx, 0x11, vga->crt[0x11] & ~0x80);
 	for(i = 0; i < NCrtx; i++)
@@ -577,7 +580,7 @@ setmode(VGAmode *vga)
 	for(i = 0; i < NAttrx; i++)
 		vgaxo(Attrx, i, vga->attribute[i]);
 
-	vgaxo(Seqx, 0x01, vga->sequencer[1]);
+	vgaxo(Seqx, 0x01, seq01);
 }
 
 static ulong