sadly, omap has its own private cons.  since i don't have an omap
to help sort this out, the junk stays.

Reference: /n/atom/patch/applied/omapconsfix
Date: Wed Jun 18 20:41:43 CES 2014
Signed-off-by: quanstro@quanstro.net

--- /sys/src/9/omap/devcons.c	Wed Jun 18 20:41:28 2014
+++ /sys/src/9/omap/devcons.c	Wed Jun 18 20:41:29 2014
@@ -5,6 +5,7 @@
 #include	"fns.h"
 #include	"../port/error.h"
 #include	"pool.h"
+
 #include	<authsrv.h>
 
 void	(*consdebug)(void) = nil;
@@ -100,8 +101,7 @@
  */
 struct {
 	Lock lk;
-//	char buf[16384];		/* normal */
-	char buf[256*1024];		/* for acpi debugging */
+	char buf[16384];
 	uint n;
 } kmesg;
 
@@ -145,9 +145,11 @@
 {
 	int m;
 	char *t;
+	int (*qw)(Queue*, void*, int);
 
-	if(!islo())
-		usewrite = 0;
+	qw = qwrite;
+	if(!islo() || !usewrite)
+		qw = qiwrite;
 
 	/*
 	 *  how many different output devices do we need?
@@ -163,37 +165,25 @@
 	 *  if there's a serial line being used as a console,
 	 *  put the message there.
 	 */
-	if(kprintoq != nil && !qisclosed(kprintoq)){
-		if(usewrite)
-			qwrite(kprintoq, str, n);
-		else
-			qiwrite(kprintoq, str, n);
-	}else if(screenputs != nil)
+	if(kprintoq != nil && !qisclosed(kprintoq))
+		qw(kprintoq, str, n);
+	else if(screenputs != nil)
 		screenputs(str, n);
 
 	if(serialoq == nil){
 		uartputs(str, n);
 		return;
 	}
-
 	while(n > 0) {
 		t = memchr(str, '\n', n);
 		if(t && !kbd.raw) {
 			m = t-str;
-			if(usewrite){
-				qwrite(serialoq, str, m);
-				qwrite(serialoq, "\r\n", 2);
-			} else {
-				qiwrite(serialoq, str, m);
-				qiwrite(serialoq, "\r\n", 2);
-			}
+			qw(serialoq, str, m);
+			qw(serialoq, "\r\n", 2);
 			n -= m+1;
 			str = t+1;
 		} else {
-			if(usewrite)
-				qwrite(serialoq, str, n);
-			else
-				qiwrite(serialoq, str, n);
+			qw(serialoq, str, n);
 			break;
 		}
 	}
@@ -246,7 +236,7 @@
 	for(i=0; i<1000; i++){
 		if(canlock(l))
 			return 1;
-		if(l->m == MACHP(m->machno))
+		if(ownlock(l))
 			return 0;
 		microdelay(100);
 	}
@@ -279,6 +269,7 @@
 	return n;
 }
 
+#pragma profile 0
 void
 panic(char *fmt, ...)
 {
@@ -288,9 +279,8 @@
 
 	kprintoq = nil;	/* don't try to write to /dev/kprint */
 
-	if(panicking)
+	if(ainc(&panicking)>1)
 		for(;;);
-	panicking = 1;
 
 	delay(20);
 	s = splhi();
@@ -309,6 +299,7 @@
 
 	exit(1);
 }
+#pragma profile 1
 
 /* libmp at least contains a few calls to sysfatal; simulate with panic */
 void
@@ -534,7 +525,7 @@
 kbdputc(Queue*, int ch)
 {
 	int i, n;
-	char buf[3];
+	char buf[UTFmax];
 	Rune r;
 	char *next;
 
@@ -583,6 +574,7 @@
 enum{
 	Qdir,
 	Qbintime,
+	Qconfig,
 	Qcons,
 	Qconsctl,
 	Qcputime,
@@ -591,6 +583,7 @@
 	Qkprint,
 	Qhostdomain,
 	Qhostowner,
+	Qmach,
 	Qnull,
 	Qosversion,
 	Qpgrpid,
@@ -604,6 +597,7 @@
 	Qtime,
 	Quser,
 	Qzero,
+	Qdebug,
 };
 
 enum
@@ -614,6 +608,7 @@
 static Dirtab consdir[]={
 	".",	{Qdir, 0, QTDIR},	0,		DMDIR|0555,
 	"bintime",	{Qbintime},	24,		0664,
+	"config",		{Qconfig},	0,		0440,
 	"cons",		{Qcons},	0,		0660,
 	"consctl",	{Qconsctl},	0,		0220,
 	"cputime",	{Qcputime},	6*NUMSIZE,	0444,
@@ -622,6 +617,7 @@
 	"hostowner",	{Qhostowner},	0,		0664,
 	"kmesg",	{Qkmesg},	0,		0440,
 	"kprint",	{Qkprint, 0, QTEXCL},	0,	DMEXCL|0440,
+	"mach",		{Qmach},	0,	0444,
 	"null",		{Qnull},	0,		0666,
 	"osversion",	{Qosversion},	0,		0444,
 	"pgrpid",	{Qpgrpid},	NUMSIZE,	0444,
@@ -635,6 +631,7 @@
 	"time",		{Qtime},	NUMSIZE+3*VLNUMSIZE,	0664,
 	"user",		{Quser},	0,		0666,
 	"zero",		{Qzero},	0,		0444,
+	"debug",	{Qdebug},	0,		0444,
 };
 
 int
@@ -757,6 +754,7 @@
 	char tmp[256];		/* must be >= 18*NUMSIZE (Qswap) */
 	int i, k, id, send;
 	vlong offset = off;
+	extern char configfile[];
 
 	if(n <= 0)
 		return n;
@@ -765,6 +763,9 @@
 	case Qdir:
 		return devdirread(c, buf, n, consdir, nelem(consdir), devgen);
 
+	case Qconfig:
+		return readstr((ulong)offset, buf, n, configfile);
+
 	case Qcons:
 		qlock(&kbd);
 		if(waserror()) {
@@ -785,8 +786,11 @@
 			}else{
 				switch(ch){
 				case '\b':
-					if(kbd.x > 0)
-						kbd.x--;
+					i = kbd.x;
+					b = kbd.line;
+					while(i > 0 && (b[--i]&0xc0) == 0x80)
+						;
+					kbd.x = i;
 					break;
 				case 0x15:	/* ^U */
 					kbd.x = 0;
@@ -870,6 +874,9 @@
 	case Quser:
 		return readstr((ulong)offset, buf, n, up->user);
 
+	case Qmach:
+		return readnum((ulong)offset, buf, n, m->machno, NUMSIZE);
+
 	case Qnull:
 		return 0;
 
@@ -968,6 +975,16 @@
 		n = readstr((ulong)offset, buf, n, tmp);
 		return n;
 
+	case Qdebug:
+	//	s = seprint(s, e, "locks %llud\n", lockstats.locks);
+	//	s = seprint(s, e, "glare %llud\n", lockstats.glare);
+	//	s = seprint(s, e, "inglare %llud\n", lockstats.inglare);
+	//	s = seprint(s, e, "qlock %llud\n", qlockstats.qlock);
+	//	s = seprint(s, e, "qlockq %llud\n", qlockstats.qlockq);
+		qiostats(tmp, tmp+sizeof tmp);
+		return readstr(offset, buf, n, tmp);
+		break;
+
 	default:
 		print("consread %#llux\n", c->qid.path);
 		error(Egreg);
@@ -992,6 +1009,10 @@
 	offset = off;
 
 	switch((ulong)c->qid.path){
+	case Qconfig:
+		error(Eperm);
+		break;
+
 	case Qcons:
 		/*
 		 * Can't page fault in putstrn, so copy the data locally.
@@ -1050,6 +1071,9 @@
 	case Quser:
 		return userwrite(a, n);
 
+	case Qmach:
+		break;
+
 	case Qnull:
 		break;
 
@@ -1071,7 +1095,6 @@
 			rebootcmd(cb->nf-1, cb->f+1);
 			break;
 		case CMpanic:
-			*(ulong*)0=0;
 			panic("/dev/reboot");
 		}
 		poperror();