[PATCH] powerpc/pseries: start rtasd before PCI probing

Greg Kurz gkurz at linux.vnet.ibm.com
Mon May 23 18:28:28 AEST 2016

A strange behaviour is observed when comparing PCI hotplug in QEMU, between
x86 and pseries. If you consider the following steps:
- start a VM
- add a PCI device via the QEMU monitor before the rtasd has started (for
  example starting the VM in paused state, or hotplug during FW or boot
- resume the VM execution

The x86 kernel detects the PCI device, but the pseries one does not.

This happens because the rtasd kernel worker is currently started under
device_initcall, while PCI probing happens earlier under subsys_initcall.

As a consequence, if we have a pending RTAS event at boot time, a message
is printed and the event is dropped.

This patch moves all the initialization of rtasd to arch_initcall, which is
run before subsys_call: this way, logging_enabled is true when the RTAS
event pops up and it is not lost anymore.

The proc fs bits stay at device_initcall because they cannot be run before

Signed-off-by: Greg Kurz <gkurz at linux.vnet.ibm.com>
 arch/powerpc/kernel/rtasd.c |   19 ++++++++++++++-----
 1 file changed, 14 insertions(+), 5 deletions(-)

diff --git a/arch/powerpc/kernel/rtasd.c b/arch/powerpc/kernel/rtasd.c
index e864b7c5884e..ad9e4e1a2d5d 100644
--- a/arch/powerpc/kernel/rtasd.c
+++ b/arch/powerpc/kernel/rtasd.c
@@ -526,10 +526,8 @@ void rtas_cancel_event_scan(void)
-static int __init rtas_init(void)
+static int __init rtas_event_scan_init(void)
-	struct proc_dir_entry *entry;
 	if (!machine_is(pseries) && !machine_is(chrp))
 		return 0;
@@ -562,13 +560,24 @@ static int __init rtas_init(void)
 		return -ENOMEM;
+	start_event_scan();
+	return 0;
+static int __init rtas_init(void)
+	struct proc_dir_entry *entry;
+	if (!machine_is(pseries) && !machine_is(chrp))
+		return 0;
 	entry = proc_create("powerpc/rtas/error_log", S_IRUSR, NULL,
 	if (!entry)
 		printk(KERN_ERR "Failed to create error_log proc entry\n");
-	start_event_scan();
 	return 0;

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