Module Name: src
Committed By: tsutsui
Date: Sat Sep 19 16:54:34 UTC 2020
Modified Files:
src/sys/arch/alpha/jensenio: com_jensenio.c
Log Message:
Possible fix for hangup on Jensen mentioned in PR/36628.
According to comments in Linux drivers/tty/serial/8250/8250.h,
https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/tty/serial/8250/8250.h?h=v5.8#n242
the driver has to set OUT1 and OUT2 lines for "some ALPHA"
otherwise "the machine locks up with endless interrupts."
Note OUT2 (MCR_IENABLE) is set in MI com_attach_subr()
so we have to set OUT1 (MCR_DSR) in the MD attachment.
The information was notified from Miod Vallat.
To generate a diff of this commit:
cvs rdiff -u -r1.15 -r1.16 src/sys/arch/alpha/jensenio/com_jensenio.c
Please note that diffs are not public domain; they are subject to the
copyright notices on the relevant files.
Modified files:
Index: src/sys/arch/alpha/jensenio/com_jensenio.c
diff -u src/sys/arch/alpha/jensenio/com_jensenio.c:1.15 src/sys/arch/alpha/jensenio/com_jensenio.c:1.16
--- src/sys/arch/alpha/jensenio/com_jensenio.c:1.15 Sat Dec 8 17:46:09 2018
+++ src/sys/arch/alpha/jensenio/com_jensenio.c Sat Sep 19 16:54:34 2020
@@ -1,4 +1,4 @@
-/* $NetBSD: com_jensenio.c,v 1.15 2018/12/08 17:46:09 thorpej Exp $ */
+/* $NetBSD: com_jensenio.c,v 1.16 2020/09/19 16:54:34 tsutsui Exp $ */
/*-
* Copyright (c) 1999 The NetBSD Foundation, Inc.
@@ -31,7 +31,7 @@
#include <sys/cdefs.h> /* RCS ID & Copyright macro defns */
-__KERNEL_RCSID(0, "$NetBSD: com_jensenio.c,v 1.15 2018/12/08 17:46:09 thorpej Exp $");
+__KERNEL_RCSID(0, "$NetBSD: com_jensenio.c,v 1.16 2020/09/19 16:54:34 tsutsui Exp $");
#include <sys/param.h>
#include <sys/systm.h>
@@ -106,6 +106,16 @@ com_jensenio_attach(device_t parent, dev
sc->sc_frequency = COM_FREQ;
+ /*
+ * According to comments in Linux drivers/tty/serial/8250/8250.h,
+ * the driver has to set OUT1 and OUT2 lines for "some ALPHA"
+ * otherwise "the machine locks up with endless interrupts."
+ * Note OUT2 (MCR_IENABLE) is set in MI com_attach_subr()
+ * so we have to set OUT1 (MCR_DSR) in the MD attachment.
+ * See also PR/36628.
+ */
+ SET(sc->sc_mcr, MCR_DRS);
+
com_attach_subr(sc);
scb_set(ja->ja_irq[0], com_jensenio_intr, jsc, IPL_VM);
