From b5a23ad40c38ab6f5d496c1b0fbd92c460e36efa Mon Sep 17 00:00:00 2001
From: balrog <balrog@c046a42c-6fe2-441c-8c8c-71466251a162>
Date: Sun, 3 Feb 2008 03:45:47 +0000
Subject: [PATCH] Do not set RTC frequency if already set (Aurelien Jarno).

git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@3954 c046a42c-6fe2-441c-8c8c-71466251a162
---
 vl.c | 5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/vl.c b/vl.c
index 3ad3625b62..deff1496ef 100644
--- a/vl.c
+++ b/vl.c
@@ -1305,11 +1305,14 @@ static void hpet_stop_timer(struct qemu_alarm_timer *t)
 static int rtc_start_timer(struct qemu_alarm_timer *t)
 {
     int rtc_fd;
+    unsigned long current_rtc_freq = 0;
 
     TFR(rtc_fd = open("/dev/rtc", O_RDONLY));
     if (rtc_fd < 0)
         return -1;
-    if (ioctl(rtc_fd, RTC_IRQP_SET, RTC_FREQ) < 0) {
+    ioctl(rtc_fd, RTC_IRQP_READ, &current_rtc_freq);
+    if (current_rtc_freq != RTC_FREQ &&
+        ioctl(rtc_fd, RTC_IRQP_SET, RTC_FREQ) < 0) {
         fprintf(stderr, "Could not configure '/dev/rtc' to have a 1024 Hz timer. This is not a fatal\n"
                 "error, but for better emulation accuracy either use a 2.6 host Linux kernel or\n"
                 "type 'echo 1024 > /proc/sys/dev/rtc/max-user-freq' as root.\n");
-- 
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