diff --git a/arch/um/include/os.h b/arch/um/include/os.h
index 700f7a76c822f763a78ae3be8c5387c465f4bda8..548f6ddd8597e1daa53a49f7c52573c9b2ae9b8a 100644
--- a/arch/um/include/os.h
+++ b/arch/um/include/os.h
@@ -318,7 +318,6 @@ extern void reboot_skas(void);
 
 /* irq.c */
 extern int os_waiting_for_events(struct irq_fd *active_fds);
-extern int os_isatty(int fd);
 extern int os_create_pollfd(int fd, int events, void *tmp_pfd, int size_tmpfds);
 extern void os_free_irq_by_cb(int (*test)(struct irq_fd *, void *), void *arg,
 		struct irq_fd *active_fds, struct irq_fd ***last_irq_ptr2);
@@ -330,9 +329,9 @@ extern void os_set_ioignore(void);
 extern void init_irq_signals(int on_sigstack);
 
 /* sigio.c */
-extern void write_sigio_workaround(void);
 extern int add_sigio_fd(int fd, int read);
 extern int ignore_sigio_fd(int fd);
+extern void maybe_sigio_broken(int fd, int read);
 
 /* skas/trap */
 extern void sig_handler_common_skas(int sig, void *sc_ptr);
diff --git a/arch/um/kernel/irq.c b/arch/um/kernel/irq.c
index 27bc58ad38fd77f102787f7d404932927049b07d..589c69a75043ab90056d3ebf983ac31edfdacef5 100644
--- a/arch/um/kernel/irq.c
+++ b/arch/um/kernel/irq.c
@@ -110,19 +110,6 @@ void sigio_handler(int sig, union uml_pt_regs *regs)
 	free_irqs();
 }
 
-static void maybe_sigio_broken(int fd, int type)
-{
-	if (os_isatty(fd)) {
-		if ((type == IRQ_WRITE) && !pty_output_sigio) {
-			write_sigio_workaround();
-			add_sigio_fd(fd, 0);
-		} else if ((type == IRQ_READ) && !pty_close_sigio) {
-			write_sigio_workaround();
-			add_sigio_fd(fd, 1);
-		}
-	}
-}
-
 static DEFINE_SPINLOCK(irq_lock);
 
 int activate_fd(int irq, int fd, int type, void *dev_id)
@@ -221,7 +208,7 @@ int activate_fd(int irq, int fd, int type, void *dev_id)
 	/* This calls activate_fd, so it has to be outside the critical
 	 * section.
 	 */
-	maybe_sigio_broken(fd, type);
+	maybe_sigio_broken(fd, (type == IRQ_READ));
 
 	return(0);
 
@@ -318,7 +305,7 @@ void reactivate_fd(int fd, int irqnum)
 	/* This calls activate_fd, so it has to be outside the critical
 	 * section.
 	 */
-	maybe_sigio_broken(fd, irq->type);
+	maybe_sigio_broken(fd, (irq->type == IRQ_READ));
 }
 
 void deactivate_fd(int fd, int irqnum)
diff --git a/arch/um/os-Linux/irq.c b/arch/um/os-Linux/irq.c
index 64c114b02701c1f5fe1a9e8e971069f0afe71145..7555bf9c33d90670bf11deaf2046e034e4ef882f 100644
--- a/arch/um/os-Linux/irq.c
+++ b/arch/um/os-Linux/irq.c
@@ -52,11 +52,6 @@ int os_waiting_for_events(struct irq_fd *active_fds)
 	return n;
 }
 
-int os_isatty(int fd)
-{
-	return isatty(fd);
-}
-
 int os_create_pollfd(int fd, int events, void *tmp_pfd, int size_tmpfds)
 {
 	if (pollfds_num == pollfds_size) {
diff --git a/arch/um/os-Linux/sigio.c b/arch/um/os-Linux/sigio.c
index 00e9388e947af4fa59442a3fdad627a82b7384e2..0d2422a7d72cd0b564ae0cebfd4a997c481be150 100644
--- a/arch/um/os-Linux/sigio.c
+++ b/arch/um/os-Linux/sigio.c
@@ -233,7 +233,7 @@ static struct pollfd *setup_initial_poll(int fd)
 	return p;
 }
 
-void write_sigio_workaround(void)
+static void write_sigio_workaround(void)
 {
 	unsigned long stack;
 	struct pollfd *p;
@@ -314,6 +314,18 @@ void write_sigio_workaround(void)
 	close(l_write_sigio_fds[1]);
 }
 
+void maybe_sigio_broken(int fd, int read)
+{
+	if(!isatty(fd))
+		return;
+
+	if((read || pty_output_sigio) && (!read || pty_close_sigio))
+		return;
+
+	write_sigio_workaround();
+	add_sigio_fd(fd, read);
+}
+
 void sigio_cleanup(void)
 {
 	if(write_sigio_pid != -1){