From 099bd73dc17ed77aa8c98323e043613b6e8f54fc Mon Sep 17 00:00:00 2001 From: Johan Hovold Date: Mon, 10 Apr 2017 11:21:38 +0200 Subject: [PATCH] serial: omap: fix runtime-pm handling on unbind An unbalanced and misplaced synchronous put was used to suspend the device on driver unbind, something which with a likewise misplaced pm_runtime_disable leads to external aborts when an open port is being removed. Unhandled fault: external abort on non-linefetch (0x1028) at 0xfa024010 ... [] (serial_omap_set_mctrl) from [] (uart_update_mctrl+0x50/0x60) [] (uart_update_mctrl) from [] (uart_shutdown+0xbc/0x138) [] (uart_shutdown) from [] (uart_hangup+0x94/0x190) [] (uart_hangup) from [] (__tty_hangup+0x404/0x41c) [] (__tty_hangup) from [] (tty_vhangup+0x1c/0x20) [] (tty_vhangup) from [] (uart_remove_one_port+0xec/0x260) [] (uart_remove_one_port) from [] (serial_omap_remove+0x40/0x60) [] (serial_omap_remove) from [] (platform_drv_remove+0x34/0x4c) Fix this up by resuming the device before deregistering the port and by suspending and disabling runtime pm only after the port has been removed. Also make sure to disable autosuspend before disabling runtime pm so that the usage count is balanced and device actually suspended before returning. Note that due to a negative autosuspend delay being set in probe, the unbalanced put would actually suspend the device on first driver unbind, while rebinding and again unbinding would result in a negative power.usage_count. Fixes: 7e9c8e7dbf3b ("serial: omap: make sure to suspend device before remove") Cc: Felipe Balbi Cc: Santosh Shilimkar Signed-off-by: Johan Hovold Acked-by: Tony Lindgren Cc: stable Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/omap-serial.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/drivers/tty/serial/omap-serial.c b/drivers/tty/serial/omap-serial.c index a4734649a0f0..50f2c5a5e450 100644 --- a/drivers/tty/serial/omap-serial.c +++ b/drivers/tty/serial/omap-serial.c @@ -1783,9 +1783,13 @@ static int serial_omap_remove(struct platform_device *dev) { struct uart_omap_port *up = platform_get_drvdata(dev); + pm_runtime_get_sync(up->dev); + + uart_remove_one_port(&serial_omap_reg, &up->port); + + pm_runtime_dont_use_autosuspend(up->dev); pm_runtime_put_sync(up->dev); pm_runtime_disable(up->dev); - uart_remove_one_port(&serial_omap_reg, &up->port); pm_qos_remove_request(&up->pm_qos_request); device_init_wakeup(&dev->dev, false); -- 2.20.1