From 2e6662efc3ecfb1f7255046a4ba6166b56b49f7b Mon Sep 17 00:00:00 2001
From: tnn <tnn@NetBSD.org>
Date: Thu, 5 Aug 2021 22:31:20 +0000
Subject: [PATCH] ssdfb: revert rev 1.14

Can't run the worker thread MPSAFE with spi(4) yet because most controller
drivers still lack MP safety. Cause issues when using multiple displays.
---
 sys/dev/i2c/ssdfb_i2c.c |  5 +++--
 sys/dev/ic/ssdfb.c      | 17 +++++++++++------
 sys/dev/ic/ssdfbvar.h   |  3 ++-
 3 files changed, 16 insertions(+), 9 deletions(-)

diff --git a/sys/dev/i2c/ssdfb_i2c.c b/sys/dev/i2c/ssdfb_i2c.c
index f05bb1462d22..90d4ba76ed60 100644
--- a/sys/dev/i2c/ssdfb_i2c.c
+++ b/sys/dev/i2c/ssdfb_i2c.c
@@ -1,4 +1,4 @@
-/* $NetBSD: ssdfb_i2c.c,v 1.10 2021/07/30 13:44:09 tnn Exp $ */
+/* $NetBSD: ssdfb_i2c.c,v 1.11 2021/08/05 22:31:20 tnn Exp $ */
 
 /*
  * Copyright (c) 2019 The NetBSD Foundation, Inc.
@@ -30,7 +30,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: ssdfb_i2c.c,v 1.10 2021/07/30 13:44:09 tnn Exp $");
+__KERNEL_RCSID(0, "$NetBSD: ssdfb_i2c.c,v 1.11 2021/08/05 22:31:20 tnn Exp $");
 
 #include <sys/param.h>
 #include <sys/device.h>
@@ -112,6 +112,7 @@ ssdfb_i2c_attach(device_t parent, device_t self, void *aux)
 	if ((flags & SSDFB_ATTACH_FLAG_PRODUCT_MASK) == SSDFB_PRODUCT_UNKNOWN)
 		flags |= SSDFB_PRODUCT_SSD1306_GENERIC;
 
+	flags |= SSDFB_ATTACH_FLAG_MPSAFE;
 	sc->sc.sc_dev = self;
 	sc->sc_i2c_tag = ia->ia_tag;
 	sc->sc_i2c_addr = ia->ia_addr;
diff --git a/sys/dev/ic/ssdfb.c b/sys/dev/ic/ssdfb.c
index 0bfcd881c159..e172889daf8c 100644
--- a/sys/dev/ic/ssdfb.c
+++ b/sys/dev/ic/ssdfb.c
@@ -1,4 +1,4 @@
-/* $NetBSD: ssdfb.c,v 1.18 2021/08/05 19:07:09 tnn Exp $ */
+/* $NetBSD: ssdfb.c,v 1.19 2021/08/05 22:31:20 tnn Exp $ */
 
 /*
  * Copyright (c) 2019 The NetBSD Foundation, Inc.
@@ -30,7 +30,7 @@
  */
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: ssdfb.c,v 1.18 2021/08/05 19:07:09 tnn Exp $");
+__KERNEL_RCSID(0, "$NetBSD: ssdfb.c,v 1.19 2021/08/05 22:31:20 tnn Exp $");
 
 #include "opt_ddb.h"
 
@@ -268,6 +268,7 @@ ssdfb_attach(struct ssdfb_softc *sc, int flags)
 	int error = 0;
 	long defattr;
 	const struct ssdfb_product *p;
+	int kt_flags;
 
 	p = ssdfb_lookup_product(flags & SSDFB_ATTACH_FLAG_PRODUCT_MASK);
 	if (p == NULL) {
@@ -393,11 +394,15 @@ ssdfb_attach(struct ssdfb_softc *sc, int flags)
 	if (sc->sc_is_console)
 		ssdfb_set_usepoll(sc, true);
 
-	mutex_init(&sc->sc_cond_mtx, MUTEX_DEFAULT, IPL_SCHED);
+	mutex_init(&sc->sc_cond_mtx, MUTEX_DEFAULT,
+	    ISSET(flags, SSDFB_ATTACH_FLAG_MPSAFE) ? IPL_SCHED : IPL_BIO);
 	cv_init(&sc->sc_cond, "ssdfb");
-	error = kthread_create(PRI_SOFTCLOCK, KTHREAD_MUSTJOIN | KTHREAD_MPSAFE,
-	    NULL, ssdfb_thread, sc,  &sc->sc_thread, "%s",
-	    device_xname(sc->sc_dev));
+	kt_flags = KTHREAD_MUSTJOIN;
+	/* XXX spi(4) is not MPSAFE yet. */
+	if (ISSET(flags, SSDFB_ATTACH_FLAG_MPSAFE))
+		kt_flags |= KTHREAD_MPSAFE;
+	error = kthread_create(PRI_SOFTCLOCK, kt_flags, NULL, ssdfb_thread, sc,
+	    &sc->sc_thread, "%s", device_xname(sc->sc_dev));
 	if (error) {
 		cv_destroy(&sc->sc_cond);
 		mutex_destroy(&sc->sc_cond_mtx);
diff --git a/sys/dev/ic/ssdfbvar.h b/sys/dev/ic/ssdfbvar.h
index 9d5f244f9a9a..c37740fbc147 100644
--- a/sys/dev/ic/ssdfbvar.h
+++ b/sys/dev/ic/ssdfbvar.h
@@ -1,4 +1,4 @@
-/* $NetBSD: ssdfbvar.h,v 1.9 2021/08/05 19:07:09 tnn Exp $ */
+/* $NetBSD: ssdfbvar.h,v 1.10 2021/08/05 22:31:20 tnn Exp $ */
 
 /*
  * Copyright (c) 2019 The NetBSD Foundation, Inc.
@@ -36,6 +36,7 @@
 #define SSDFB_ATTACH_FLAG_UPSIDEDOWN		0x00000100
 #define SSDFB_ATTACH_FLAG_INVERSE		0x00000200
 #define SSDFB_ATTACH_FLAG_CONSOLE		0x00000400
+#define SSDFB_ATTACH_FLAG_MPSAFE		0x00000800
 
 /*
  * Fundamental commands