[Qemu-devel] [PATCH v6 3/3] Change driftfix default value to slew

[Crístian Viana]

Windows 2008+ is very sensitive to missed ticks. The RTC is used by default as
the time source. If driftfix is not enabled, Windows is prone to
blue screening.

Signed-off-by: Crístian Viana <address@hidden>
---
 hw/mc146818rtc.c |    2 +-
 vl.c             |   11 ++++++++++-
 2 files changed, 11 insertions(+), 2 deletions(-)

diff --git a/hw/mc146818rtc.c b/hw/mc146818rtc.c
index 3777f85..dfd7ee6 100644
--- a/hw/mc146818rtc.c
+++ b/hw/mc146818rtc.c
@@ -686,7 +686,7 @@ ISADevice *rtc_init(ISABus *bus, int base_year, qemu_irq 
intercept_irq)
 static Property mc146818rtc_properties[] = {
     DEFINE_PROP_INT32("base_year", RTCState, base_year, 1980),
     DEFINE_PROP_LOSTTICKPOLICY("lost_tick_policy", RTCState,
-                               lost_tick_policy, LOST_TICK_DISCARD),
+                               lost_tick_policy, LOST_TICK_SLEW),
     DEFINE_PROP_END_OF_LIST(),
 };
 
diff --git a/vl.c b/vl.c
index 46248b9..c09ed5e 100644
--- a/vl.c
+++ b/vl.c
@@ -559,7 +559,16 @@ static void configure_rtc(QemuOpts *opts)
 
             qdev_prop_register_global_list(slew_lost_ticks);
         } else if (!strcmp(value, "none")) {
-            /* discard is default */
+            static GlobalProperty discard_lost_ticks[] = {
+                {
+                    .driver   = "mc146818rtc",
+                    .property = "lost_tick_policy",
+                    .value    = "discard",
+                },
+                { /* end of list */ }
+            };
+
+            qdev_prop_register_global_list(discard_lost_ticks);
         } else {
             fprintf(stderr, "qemu: invalid option value '%s'\n", value);
             exit(1);
-- 
1.7.9.5