From: Kei Tokunaga <ktokunag@redhat.com>
Subject: [RHEL5 PATCH] SHPCHP driver doesn't work if the system was under  heavy load
Date: Mon, 20 Nov 2006 14:47:08 -0500
Bugzilla: 215561
Message-Id: <4562063C.6080603@redhat.com>
Changelog: SHPCHP driver doesn't work if the system was under heavy load


BZ215561
https://bugzilla.redhat.com/bugzilla/show_bug.cgi?id=215561

I'm sending this email in reply to email about BZ211679
since BZ215561 depends on BZ211679.

This patch is in upstream.
http://www.kernel.org/git/?p=linux/kernel/git/torvalds/linux-2.6.git;a=blobdiff_plain;h=4826dd158deb66d74909199271726d14260a9bbd;hp=446e9beff046e01548c2b2c6de61c76fe0779199

Powering on/off operation to hotplug slots using SHPC fails
under heavy load and displays the following error message:

   shpchp: Command not completed in 1000 msec
   shpchp: hpc_slot_disable: Write command failed!
   shpchp: remove_board: Issue of Slot Disable command failed

This patch fixes the issue.

This patch applies to -2.6.18-1.2747.el5 with BZ211679's
patch applied.  It was tested on the previous RHEL5 release
before beta2 was out.  So, we are doing some testing on beta2
just in case.

NOTE: As I stated, this bug depends on BZ211679, which I have
already submitted a fix-patch to rhkernel-list.

Thanks,
Kei


---

 linux-2.6.18-1.2747.el5-kei/drivers/pci/hotplug/shpchp_hpc.c |   14 +++++++----
 1 file changed, 9 insertions(+), 5 deletions(-)

diff -puN drivers/pci/hotplug/shpchp_hpc.c~bz215561-fix-SHPCHP-under_heavy_load drivers/pci/hotplug/shpchp_hpc.c
--- linux-2.6.18-1.2747.el5/drivers/pci/hotplug/shpchp_hpc.c~bz215561-fix-SHPCHP-under_heavy_load	2006-11-17 15:40:56.000000000 -0500
+++ linux-2.6.18-1.2747.el5-kei/drivers/pci/hotplug/shpchp_hpc.c	2006-11-17 15:40:56.000000000 -0500
@@ -302,6 +302,12 @@ static void start_int_poll_timer(struct 
 	add_timer(&php_ctlr->int_poll_timer);
 }
 
+static inline int is_ctrl_busy(struct controller *ctrl)
+{
+	u16 cmd_status = shpc_readw(ctrl, CMD_STATUS);
+	return cmd_status & 0x1;
+}
+
 /*
  * Returns 1 if SHPC finishes executing a command within 1 sec,
  * otherwise returns 0.
@@ -309,16 +315,14 @@ static void start_int_poll_timer(struct 
 static inline int shpc_poll_ctrl_busy(struct controller *ctrl)
 {
 	int i;
-	u16 cmd_status = shpc_readw(ctrl, CMD_STATUS);
 
-	if (!(cmd_status & 0x1))
+	if (!is_ctrl_busy(ctrl))
 		return 1;
 
 	/* Check every 0.1 sec for a total of 1 sec */
 	for (i = 0; i < 10; i++) {
 		msleep(100);
-		cmd_status = shpc_readw(ctrl, CMD_STATUS);
-		if (!(cmd_status & 0x1))
+		if (!is_ctrl_busy(ctrl))
 			return 1;
 	}
 
@@ -336,7 +340,7 @@ static inline int shpc_wait_cmd(struct c
 	else
 		rc = wait_event_interruptible_timeout(ctrl->queue,
 						!ctrl->cmd_busy, timeout);
-	if (!rc) {
+	if (!rc && is_ctrl_busy(ctrl)) {
 		retval = -EIO;
 		err("Command not completed in 1000 msec\n");
 	} else if (rc < 0) {

_