lkml.org 
[lkml]   [2013]   [Sep]   [23]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH] driver core: prevent deferred probe with platform_driver_probe
Date
Prevent drivers relying on platform_driver_probe from requesting
deferred probing in order to avoid further futile probe attempts (either
the driver has been unregistered or its probe function has been set to
platform_drv_probe_fail when probing is retried).

Note that several platform drivers currently return subsystem errors
from probe and that these can include -EPROBE_DEFER (e.g. if a gpio
request fails).

Signed-off-by: Johan Hovold <jhovold@gmail.com>
---
drivers/base/platform.c | 17 +++++++++++++----
include/linux/platform_device.h | 1 +
2 files changed, 14 insertions(+), 4 deletions(-)

diff --git a/drivers/base/platform.c b/drivers/base/platform.c
index 4f8bef3..47051cd 100644
--- a/drivers/base/platform.c
+++ b/drivers/base/platform.c
@@ -488,6 +488,11 @@ static int platform_drv_probe(struct device *_dev)
if (ret && ACPI_HANDLE(_dev))
acpi_dev_pm_detach(_dev, true);

+ if (drv->prevent_deferred_probe && ret == -EPROBE_DEFER) {
+ dev_warn(_dev, "probe deferral not supported\n");
+ ret = -ENXIO;
+ }
+
return ret;
}

@@ -553,8 +558,7 @@ EXPORT_SYMBOL_GPL(platform_driver_unregister);
/**
* platform_driver_probe - register driver for non-hotpluggable device
* @drv: platform driver structure
- * @probe: the driver probe routine, probably from an __init section,
- * must not return -EPROBE_DEFER.
+ * @probe: the driver probe routine, probably from an __init section
*
* Use this instead of platform_driver_register() when you know the device
* is not hotpluggable and has already been registered, and you want to
@@ -565,8 +569,7 @@ EXPORT_SYMBOL_GPL(platform_driver_unregister);
* into system-on-chip processors, where the controller devices have been
* configured as part of board setup.
*
- * This is incompatible with deferred probing so probe() must not
- * return -EPROBE_DEFER.
+ * Note that this is incompatible with deferred probing.
*
* Returns zero if the driver registered and bound to a device, else returns
* a negative error code and with the driver not registered.
@@ -576,6 +579,12 @@ int __init_or_module platform_driver_probe(struct platform_driver *drv,
{
int retval, code;

+ /*
+ * Prevent driver from requesting probe deferral to avoid further
+ * futile probe attempts.
+ */
+ drv->prevent_deferred_probe = true;
+
/* make sure driver won't have bind/unbind attributes */
drv->driver.suppress_bind_attrs = true;

diff --git a/include/linux/platform_device.h b/include/linux/platform_device.h
index ce8e4ff..16f6654 100644
--- a/include/linux/platform_device.h
+++ b/include/linux/platform_device.h
@@ -178,6 +178,7 @@ struct platform_driver {
int (*resume)(struct platform_device *);
struct device_driver driver;
const struct platform_device_id *id_table;
+ bool prevent_deferred_probe;
};

#define to_platform_driver(drv) (container_of((drv), struct platform_driver, \
--
1.8.3.2


\
 
 \ /
  Last update: 2013-09-23 11:41    [W:0.092 / U:1.004 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site