From: Philippe Mathieu-Daudé <f4bug@amsat.org>

Clock canonical name is set in device_set_realized (see the block
added to hw/core/qdev.c in commit 0e6934f264).
If we connect a clock after the device is realized, this code is
not executed. This is currently not a problem as this name is only
used for trace events, however this disrupt tracing.

Add a comment to document qdev_connect_clock_in() must be called
before the device is realized, and assert this condition.

Signed-off-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
Reviewed-by: Alistair Francis <alistair.francis@wdc.com>
Message-id: 20200803105647.22223-5-f4bug@amsat.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---
 include/hw/qdev-clock.h | 2 ++
 hw/core/qdev-clock.c    | 1 +
 2 files changed, 3 insertions(+)

diff --git a/include/hw/qdev-clock.h b/include/hw/qdev-clock.h
index a897f7c9d0f..64ca4d266f2 100644
--- a/include/hw/qdev-clock.h
+++ b/include/hw/qdev-clock.h
@@ -70,6 +70,8 @@ Clock *qdev_get_clock_out(DeviceState *dev, const char *name);
  *
  * Set the source clock of input clock @name of device @dev to @source.
  * @source period update will be propagated to @name clock.
+ *
+ * Must be called before @dev is realized.
  */
 void qdev_connect_clock_in(DeviceState *dev, const char *name, Clock *source);
 
diff --git a/hw/core/qdev-clock.c b/hw/core/qdev-clock.c
index f139b68b881..47ecb5b4fae 100644
--- a/hw/core/qdev-clock.c
+++ b/hw/core/qdev-clock.c
@@ -186,5 +186,6 @@ Clock *qdev_alias_clock(DeviceState *dev, const char *name,
 
 void qdev_connect_clock_in(DeviceState *dev, const char *name, Clock *source)
 {
+    assert(!dev->realized);
     clock_set_source(qdev_get_clock_in(dev, name), source);
 }
-- 
2.20.1