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, 8 insertions, 14 deletions

diff --git a/kernel/drivers/tty/serial/8250/8250_port.c b/kernel/drivers/tty/serial/8250/8250_port.c
index 5568d70ee..a0b9e8546 100644
--- a/kernel/drivers/tty/serial/8250/8250_port.c
+++ b/kernel/drivers/tty/serial/8250/8250_port.c
@@ -714,22 +714,16 @@ static int size_fifo(struct uart_8250_port *up)
  */
 static unsigned int autoconfig_read_divisor_id(struct uart_8250_port *p)
 {
-	unsigned char old_dll, old_dlm, old_lcr;
-	unsigned int id;
+	unsigned char old_lcr;
+	unsigned int id, old_dl;
 
 	old_lcr = serial_in(p, UART_LCR);
 	serial_out(p, UART_LCR, UART_LCR_CONF_MODE_A);
+	old_dl = serial_dl_read(p);
+	serial_dl_write(p, 0);
+	id = serial_dl_read(p);
+	serial_dl_write(p, old_dl);
 
-	old_dll = serial_in(p, UART_DLL);
-	old_dlm = serial_in(p, UART_DLM);
-
-	serial_out(p, UART_DLL, 0);
-	serial_out(p, UART_DLM, 0);
-
-	id = serial_in(p, UART_DLL) | serial_in(p, UART_DLM) << 8;
-
-	serial_out(p, UART_DLL, old_dll);
-	serial_out(p, UART_DLM, old_dlm);
 	serial_out(p, UART_LCR, old_lcr);
 
 	return id;
@@ -2850,9 +2844,9 @@ void serial8250_console_write(struct uart_8250_port *up, const char *s,
 
 	serial8250_rpm_get(up);
 
-	if (port->sysrq)
+	if (port->sysrq || oops_in_progress)
 		locked = 0;
-	else if (oops_in_progress || in_kdb_printk())
+	else if (in_kdb_printk())
 		locked = spin_trylock_irqsave(&port->lock, flags);
 	else
 		spin_lock_irqsave(&port->lock, flags);