Re: [PATCH 5/7] serial: omap: Fix PM regression with deferred probe for pm_runtime_reinit
From: Ulf Hansson <hidden>
Date: 2016-02-12 12:52:44
Also in:
linux-arm-kernel, linux-i2c, linux-mmc, linux-omap, linux-spi
On 11 February 2016 at 00:02, Tony Lindgren [off-list ref] wrote:
Commit 5de85b9d57ab ("PM / runtime: Re-init runtime PM states at probe
error and driver unbind") introduced pm_runtime_reinit() that is used
to reinitialize PM runtime after -EPROBE_DEFER. This allows shutting
down the device after a failed probe.
However, for drivers using pm_runtime_use_autosuspend() this can cause
a state where suspend callback is never called after -EPROBE_DEFER.
On the following device driver probe, hardware state is different from
the PM runtime state causing omap_device to produce the following
error:
omap_device_enable() called from invalid state 1
And with omap_device and omap hardware being picky for PM, this will
block any deeper idle states in hardware.
The solution is to fix the drivers to follow the PM runtime documentation:
1. For sections of code that needs the device disabled, use
pm_runtime_put_sync_suspend() if pm_runtime_set_autosuspend() has
been set.
2. For driver exit code, use pm_runtime_dont_use_autosuspend() before
pm_runtime_put_sync() if pm_runtime_use_autosuspend() has been
set.
Fixes: 5de85b9d57ab ("PM / runtime: Re-init runtime PM states at probe
error and driver unbind")
Cc: linux-serial@vger.kernel.org
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Kevin Hilman <khilman@baylibre.com>
Cc: Nishanth Menon <nm@ti.com>
Cc: Rafael J. Wysocki <rafael@kernel.org>
Cc: Ulf Hansson <redacted>
Cc: Tero Kristo <redacted>
Signed-off-by: Tony Lindgren <tony@atomide.com>Acked-by: Ulf Hansson <redacted> Kind regards Uffe
quoted hunk ↗ jump to hunk
--- Greg & Peter, I'd like to merge this along with other related fixes via the ARM SoC tree if no objections, please review and ack if this look OK to you. --- drivers/tty/serial/omap-serial.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)diff --git a/drivers/tty/serial/omap-serial.c b/drivers/tty/serial/omap-serial.c index b645f92..5c43f75 100644 --- a/drivers/tty/serial/omap-serial.c +++ b/drivers/tty/serial/omap-serial.c@@ -1708,7 +1708,8 @@ static int serial_omap_probe(struct platform_device *pdev) return 0; err_add_port: - pm_runtime_put(&pdev->dev); + pm_runtime_dont_use_autosuspend(&pdev->dev); + pm_runtime_put_sync(&pdev->dev); pm_runtime_disable(&pdev->dev); pm_qos_remove_request(&up->pm_qos_request); device_init_wakeup(up->dev, false);@@ -1721,6 +1722,7 @@ static int serial_omap_remove(struct platform_device *dev) { struct uart_omap_port *up = platform_get_drvdata(dev); + 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); --2.7.0