From 73127595963d9c35f76215ba4225b25f3d0395fd Mon Sep 17 00:00:00 2001
From: Luke Dashjr <luke-jr+git@utopios.org>
Date: Fri, 6 Apr 2012 10:35:41 -0400
Subject: [PATCH] Workaround Icarus UART failures by reopening the tty every
 scanhash

ngzhang says the USB-UART chip isn't stable on some computers, and I'm experiencing some weirdness myself.
This workaround seems to fix it (tested for over 48 hours, whereas failure is usually in well under 5 hours).
---
 icarus.c | 28 ++++++++++++++--------------
 1 file changed, 14 insertions(+), 14 deletions(-)

diff --git a/icarus.c b/icarus.c
index 276cd8c7..13e31ca1 100644
--- a/icarus.c
+++ b/icarus.c
@@ -225,15 +225,6 @@ static bool icarus_prepare(struct thr_info *thr)
 
 	struct timeval now;
 
-	int fd = icarus_open(icarus->device_path);
-	if (unlikely(-1 == fd)) {
-		applog(LOG_ERR, "Failed to open Icarus on %s",
-		       icarus->device_path);
-		return false;
-	}
-
-	icarus->device_fd = fd;
-
 	applog(LOG_INFO, "Opened Icarus on %s", icarus->device_path);
 	gettimeofday(&now, NULL);
 	get_datestamp(icarus->init, &now);
@@ -255,7 +246,13 @@ static uint64_t icarus_scanhash(struct thr_info *thr, struct work *work,
 	time_t t = 0;
 
 	icarus = thr->cgpu;
-	fd = icarus->device_fd;
+
+	fd = icarus_open(icarus->device_path);
+	if (unlikely(-1 == fd)) {
+		applog(LOG_ERR, "Failed to open Icarus on %s",
+		       icarus->device_path);
+		return 0;
+	}
 
 	memset(ob_bin, 0, sizeof(ob_bin));
 	memcpy(ob_bin, work->midstate, 32);
@@ -266,8 +263,10 @@ static uint64_t icarus_scanhash(struct thr_info *thr, struct work *work,
 	tcflush(fd, TCOFLUSH);
 #endif
 	ret = icarus_write(fd, ob_bin, sizeof(ob_bin));
-	if (ret)
+	if (ret) {
+		icarus_close(fd);
 		return 0;	/* This should never happen */
+	}
 
 	ob_hex = bin2hex(ob_bin, sizeof(ob_bin));
 	if (ob_hex) {
@@ -291,8 +290,10 @@ static uint64_t icarus_scanhash(struct thr_info *thr, struct work *work,
 
 	memcpy((char *)&nonce, nonce_bin, sizeof(nonce_bin));
 
-        if (nonce == 0 && ret)
+	if (nonce == 0 && ret) {
+		icarus_close(fd);
                 return 0xffffffff;
+	}
 
 #ifndef __BIG_ENDIAN__
 	nonce = swab32(nonce);
@@ -310,6 +311,7 @@ static uint64_t icarus_scanhash(struct thr_info *thr, struct work *work,
                         hash_count <<= 1;
         }
 
+	icarus_close(fd);
         return hash_count;
 }
 
@@ -323,8 +325,6 @@ static void icarus_shutdown(struct thr_info *thr)
 		if (icarus->device_path)
 			free(icarus->device_path);
 
-		close(icarus->device_fd);
-
 		devices[icarus->device_id] = NULL;
 		free(icarus);