Acquire console lock before enabling and writing to console-uart
to avoid any recursive prints from console write.
for ex:
--> printk
--> uart_console_write
--> get_sync
--> printk from omap_device enable
--> uart_console write
Use RPM_SUSPENDING check to avoid below scenario during bootup
As during bootup console_lock is not available.
--> uart_add_one_port
--> console_register
--> console_lock
--> console_unlock
--> call_console_drivers (here yet console_lock is not released)
--> uart_console_write
Acked-by: Alan Cox <alan@xxxxxxxxxxxxxxx>
Signed-off-by: Govindraj.R <govindraj.raja@xxxxxx>
---
drivers/tty/serial/omap-serial.c | 20 +++++++++++++++++++-
1 files changed, 19 insertions(+), 1 deletions(-)
diff --git a/drivers/tty/serial/omap-serial.c b/drivers/tty/serial/omap-serial.c
index 897416f..ee94291 100644
--- a/drivers/tty/serial/omap-serial.c
+++ b/drivers/tty/serial/omap-serial.c
@@ -1008,7 +1008,22 @@ serial_omap_console_write(struct console *co, const char *s,
struct uart_omap_port *up = serial_omap_console_ports[co->index];
unsigned long flags;
unsigned int ier;
- int locked = 1;
+ int console_lock = 0, locked = 1;
+
+ if (console_trylock())
+ console_lock = 1;
+
+ /*
+ * If console_lock is not available and we are in suspending
+ * state then we can avoid the console usage scenario
+ * as this may introduce recursive prints.
+ * Basically this scenario occurs during boot while
+ * printing debug bootlogs.
+ */
+
+ if (!console_lock &&
+ up->pdev->dev.power.runtime_status == RPM_SUSPENDING)
+ return;
local_irq_save(flags);
if (up->port.sysrq)
@@ -1044,6 +1059,9 @@ serial_omap_console_write(struct console *co, const char *s,
if (up->msr_saved_flags)
check_modem_status(up);
+ if (console_lock)
+ console_unlock();
+
serial_omap_port_disable(up);
if (locked)
spin_unlock(&up->port.lock);
--
1.7.0.4
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