From: Alan Cox <alan@linux.intel.com>
Date: Fri, 17 Aug 2018 09:44:49 +0000 (+0100)
Subject: tty: improve behaviour of O_NDELAY
X-Git-Url: https://git.ndcode.org/public/gitweb.cgi?a=commitdiff_plain;h=ca65d8a7fcc2217406320d4ae09a26bf68555632;p=FUZIX.git

tty: improve behaviour of O_NDELAY

We want to bale out on a polled output port on a reschedule not just sit
assuming the bits will go out shortly
---

diff --git a/Kernel/tty.c b/Kernel/tty.c
index 169cd5ea..eba4444f 100644
--- a/Kernel/tty.c
+++ b/Kernel/tty.c
@@ -512,12 +512,14 @@ uint8_t tty_putc_maywait(uint8_t minor, unsigned char c, uint8_t flag)
 				udata.u_error = EINTR;
 				return 1;
 			}
-			if (t == TTY_READY_LATER && flag) {
-				udata.u_error = EAGAIN;
-				return 1;
-			}
 			if (t != TTY_READY_SOON || need_reschedule()){
-				irqflags_t irq = di();
+				irqflags_t irq;
+
+				if (flag) {
+					udata.u_error = EAGAIN;
+					return 1;
+				}
+				irq = di();
 				tty_sleeping(minor);
 				psleep(&ttydata[minor]);
 				irqrestore(irq);