[PATCH] pmac_zilog: sleep fix

From: Benjamin Herrenschmidt <benh@kernel.crashing.org>

This patch fix a problem with semaphore usage on wakeup from sleep in
pmac_zilog (crashing some laptops on wakeup).

diff --git a/drivers/serial/pmac_zilog.c b/drivers/serial/pmac_zilog.c
index 2c9e2092ba9be75cd68e8ff37a1f5fe3446dfaa3..cef6c09961d2be942ab6ad6d9a662a712113c0b8 100644 (file)
--- a/drivers/serial/pmac_zilog.c
+++ b/drivers/serial/pmac_zilog.c
@@ -1563,15 +1563,21 @@ static int pmz_detach(struct macio_dev *mdev)
 static int pmz_suspend(struct macio_dev *mdev, u32 pm_state)
 {
        struct uart_pmac_port *uap = dev_get_drvdata(&mdev->ofdev.dev);
-       struct uart_state *state = pmz_uart_reg.state + uap->port.line;
+       struct uart_state *state;
        unsigned long flags;
 
-       if (uap == NULL)
+       if (uap == NULL) {
+               printk("HRM... pmz_suspend with NULL uap\n");
                return 0;
+       }
 
        if (pm_state == mdev->ofdev.dev.power_state || pm_state < 2)
                return 0;
 
+       pmz_debug("suspend, switching to state %d\n", pm_state);
+
+       state = pmz_uart_reg.state + uap->port.line;
+
        down(&pmz_irq_sem);
        down(&state->sem);
 
@@ -1607,6 +1613,8 @@ static int pmz_suspend(struct macio_dev *mdev, u32 pm_state)
        up(&state->sem);
        up(&pmz_irq_sem);
 
+       pmz_debug("suspend, switching complete\n");
+
        mdev->ofdev.dev.power_state = pm_state;
 
        return 0;
@@ -1616,7 +1624,7 @@ static int pmz_suspend(struct macio_dev *mdev, u32 pm_state)
 static int pmz_resume(struct macio_dev *mdev)
 {
        struct uart_pmac_port *uap = dev_get_drvdata(&mdev->ofdev.dev);
-       struct uart_state *state = pmz_uart_reg.state + uap->port.line;
+       struct uart_state *state;
        unsigned long flags;
        int pwr_delay;
 
@@ -1626,6 +1634,10 @@ static int pmz_resume(struct macio_dev *mdev)
        if (mdev->ofdev.dev.power_state == 0)
                return 0;
        
+       pmz_debug("resume, switching to state 0\n");
+
+       state = pmz_uart_reg.state + uap->port.line;
+
        down(&pmz_irq_sem);
        down(&state->sem);
 
@@ -1658,6 +1670,7 @@ static int pmz_resume(struct macio_dev *mdev)
                enable_irq(uap->port.irq);
        }
 
+ bail:
        up(&state->sem);
        up(&pmz_irq_sem);
 
@@ -1670,7 +1683,8 @@ static int pmz_resume(struct macio_dev *mdev)
                schedule_timeout((pwr_delay * HZ)/1000);
        }
 
- bail:
+       pmz_debug("resume, switching complete\n");
+
        mdev->ofdev.dev.power_state = 0;
 
        return 0;