Upgrade to 4.4.50-rt62

The current kernel is based on rt kernel v4.4.6-rt14. We will upgrade it
to 4.4.50-rt62.
The command to achieve it is:
a) Clone a git repo from
git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-stable-rt.git

b) Get the diff between this two changesets:
git diff 640eca2901f3435e616157b11379d3223a44b391
705619beeea1b0b48219a683fd1a901a86fdaf5e

where the two commits are:
[yjiang5@jnakajim-build linux-stable-rt]$ git show --oneline --name-only
640eca2901f3435e616157b11379d3223a44b391
640eca2901f3 v4.4.6-rt14
localversion-rt
[yjiang5@jnakajim-build linux-stable-rt]$ git show --oneline --name-only
705619beeea1b0b48219a683fd1a901a86fdaf5e
705619beeea1 Linux 4.4.50-rt62
localversion-rt

c) One patch has been backported thus revert the patch before applying.

 filterdiff -p1 -x scripts/package/Makefile
~/tmp/v4.4.6-rt14-4.4.50-rt62.diff  |patch -p1 --dry-run

Upstream status: backport

Change-Id: I244d57a32f6066e5a5b9915f9fbf99e7bbca6e01
Signed-off-by: Yunhong Jiang <yunhong.jiang@linux.intel.com>

1 files changed, 37 insertions, 4 deletions

diff --git a/kernel/drivers/acpi/ec.c b/kernel/drivers/acpi/ec.c
index b420fb466..43f20328f 100644
--- a/kernel/drivers/acpi/ec.c
+++ b/kernel/drivers/acpi/ec.c
@@ -101,6 +101,7 @@ enum ec_command {
 #define ACPI_EC_UDELAY_POLL	550	/* Wait 1ms for EC transaction polling */
 #define ACPI_EC_CLEAR_MAX	100	/* Maximum number of events to query
 					 * when trying to clear the EC */
+#define ACPI_EC_MAX_QUERIES	16	/* Maximum number of parallel queries */
 
 enum {
 	EC_FLAGS_QUERY_PENDING,		/* Query is pending */
@@ -121,6 +122,10 @@ static unsigned int ec_delay __read_mostly = ACPI_EC_DELAY;
 module_param(ec_delay, uint, 0644);
 MODULE_PARM_DESC(ec_delay, "Timeout(ms) waited until an EC command completes");
 
+static unsigned int ec_max_queries __read_mostly = ACPI_EC_MAX_QUERIES;
+module_param(ec_max_queries, uint, 0644);
+MODULE_PARM_DESC(ec_max_queries, "Maximum parallel _Qxx evaluations");
+
 static bool ec_busy_polling __read_mostly;
 module_param(ec_busy_polling, bool, 0644);
 MODULE_PARM_DESC(ec_busy_polling, "Use busy polling to advance EC transaction");
@@ -174,6 +179,7 @@ static void acpi_ec_event_processor(struct work_struct *work);
 
 struct acpi_ec *boot_ec, *first_ec;
 EXPORT_SYMBOL(first_ec);
+static struct workqueue_struct *ec_query_wq;
 
 static int EC_FLAGS_VALIDATE_ECDT; /* ASUStec ECDTs need to be validated */
 static int EC_FLAGS_SKIP_DSDT_SCAN; /* Not all BIOS survive early DSDT scan */
@@ -1097,7 +1103,7 @@ static int acpi_ec_query(struct acpi_ec *ec, u8 *data)
 	 * work queue execution.
 	 */
 	ec_dbg_evt("Query(0x%02x) scheduled", value);
-	if (!schedule_work(&q->work)) {
+	if (!queue_work(ec_query_wq, &q->work)) {
 		ec_dbg_evt("Query(0x%02x) overlapped", value);
 		result = -EBUSY;
 	}
@@ -1657,15 +1663,41 @@ static struct acpi_driver acpi_ec_driver = {
 		},
 };
 
+static inline int acpi_ec_query_init(void)
+{
+	if (!ec_query_wq) {
+		ec_query_wq = alloc_workqueue("kec_query", 0,
+					      ec_max_queries);
+		if (!ec_query_wq)
+			return -ENODEV;
+	}
+	return 0;
+}
+
+static inline void acpi_ec_query_exit(void)
+{
+	if (ec_query_wq) {
+		destroy_workqueue(ec_query_wq);
+		ec_query_wq = NULL;
+	}
+}
+
 int __init acpi_ec_init(void)
 {
-	int result = 0;
+	int result;
 
+	/* register workqueue for _Qxx evaluations */
+	result = acpi_ec_query_init();
+	if (result)
+		goto err_exit;
 	/* Now register the driver for the EC */
 	result = acpi_bus_register_driver(&acpi_ec_driver);
-	if (result < 0)
-		return -ENODEV;
+	if (result)
+		goto err_exit;
 
+err_exit:
+	if (result)
+		acpi_ec_query_exit();
 	return result;
 }
 
@@ -1675,5 +1707,6 @@ static void __exit acpi_ec_exit(void)
 {
 
 	acpi_bus_unregister_driver(&acpi_ec_driver);
+	acpi_ec_query_exit();
 }
 #endif	/* 0 */