Patch "serial: omap: fix runtime-pm handling on unbind" has been added to the 4.10-stable tree
Subsystems (2)
This is a note to let you know that I've just added the patch titled
serial: omap: fix runtime-pm handling on unbind
to the 4.10-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
serial-omap-fix-runtime-pm-handling-on-unbind.patch
and it can be found in the queue-4.10 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.
Quoted 1 line
From
099bd73dc17ed77aa8c98323e043613b6e8f54fcMon Sep 17 00:00:00 2001
From: Johan Hovold <[email protected]>
Date: Mon, 10 Apr 2017 11:21:38 +0200
Subject: serial: omap: fix runtime-pm handling on unbind
From: Johan Hovold <[email protected]>
commit 099bd73dc17ed77aa8c98323e043613b6e8f54fc upstream.
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
...
[<c046e760>] (serial_omap_set_mctrl) from [<c046a064>] (uart_update_mctrl+0x50/0x60) [<c046a064>] (uart_update_mctrl) from [<c046a400>] (uart_shutdown+0xbc/0x138) [<c046a400>] (uart_shutdown) from [<c046bd2c>] (uart_hangup+0x94/0x190) [<c046bd2c>] (uart_hangup) from [<c045b760>] (__tty_hangup+0x404/0x41c) [<c045b760>] (__tty_hangup) from [<c045b794>] (tty_vhangup+0x1c/0x20) [<c045b794>] (tty_vhangup) from [<c046ccc8>] (uart_remove_one_port+0xec/0x260) [<c046ccc8>] (uart_remove_one_port) from [<c046ef4c>] (serial_omap_remove+0x40/0x60) [<c046ef4c>] (serial_omap_remove) from [<c04845e8>] (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.
--- drivers/tty/serial/omap-serial.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-)
drivers/tty/serial/omap-serial.c +5 -1
@@ -1725,9 +1725,13 @@ static int serial_omap_remove(struct pla {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);
Patches currently in stable-queue which might be from [email protected] are
queue-4.10/usb-serial-ftdi_sio-add-device-id-for-microsemi-arrow-sf2plus-dev-kit.patch queue-4.10/bluetooth-hci_bcm-add-missing-tty-device-sanity-check.patch queue-4.10/bluetooth-hci_intel-add-missing-tty-device-sanity-check.patch queue-4.10/serial-omap-fix-runtime-pm-handling-on-unbind.patch queue-4.10/serial-omap-suspend-device-on-probe-errors.patch queue-4.10/staging-gdm724x-gdm_mux-fix-use-after-free-on-module-unload.patch