Re: 2.6.21-mm2: HDAPS? BUG: at kernel/mutex.c:311

Dmitry Torokhov
2007-05-12T05:12:59Z

On Friday 11 May 2007 20:53, Andrew Morton wrote:
> Ho hum.  I suppose a suitable workaround would be to convert hdaps_mtx back
> into a semaphore.  ug.

Actually I was looking for victimes^Wvolunteers to test the patch below.
It gets rid of _trylock business.

--
Dmitry

HWMON: hdaps - convert to use input-polldev

Switch to using input-polldev skeleton instead of implementing
polling loop by itself.

Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
---

drivers/hwmon/Kconfig | 1
drivers/hwmon/hdaps.c | 55 +++++++++++++++++++++-----------------------------
2 files changed, 25 insertions(+), 31 deletions(-)

Index: work/drivers/hwmon/Kconfig
===================================================================
--- work.orig/drivers/hwmon/Kconfig
+++ work/drivers/hwmon/Kconfig
@@ -602,6 +602,7 @@ config SENSORS_W83627EHF
config SENSORS_HDAPS
tristate "IBM Hard Drive Active Protection System (hdaps)"
depends on INPUT && X86
+ select INPUT_POLLDEV
default n
help
This driver provides support for the IBM Hard Drive Active Protection
Index: work/drivers/hwmon/hdaps.c
===================================================================
--- work.orig/drivers/hwmon/hdaps.c
+++ work/drivers/hwmon/hdaps.c
@@ -28,7 +28,7 @@

#include <linux/delay.h>
#include <linux/platform_device.h>
-#include <linux/input.h>
+#include <linux/input-polldev.h>
#include <linux/kernel.h>
#include <linux/mutex.h>
#include <linux/module.h>
@@ -61,13 +61,12 @@
#define INIT_TIMEOUT_MSECS 4000 /* wait up to 4s for device init ... */
#define INIT_WAIT_MSECS 200 /* ... in 200ms increments */

-#define HDAPS_POLL_PERIOD (HZ/20) /* poll for input every 1/20s */
+#define HDAPS_POLL_INTERVAL 50 /* poll for input every 1/20s (50 ms)*/
#define HDAPS_INPUT_FUZZ 4 /* input event threshold */
#define HDAPS_INPUT_FLAT 4

-static struct timer_list hdaps_timer;
static struct platform_device *pdev;
-static struct input_dev *hdaps_idev;
+static struct input_polled_dev *hdaps_idev;
static unsigned int hdaps_invert;
static u8 km_activity;
static int rest_x;
@@ -323,24 +322,19 @@ static void hdaps_calibrate(void)
__hdaps_read_pair(HDAPS_PORT_XPOS, HDAPS_PORT_YPOS, &rest_x, &rest_y);
}

-static void hdaps_mousedev_poll(unsigned long unused)
+static void hdaps_mousedev_poll(struct input_polled_dev *dev)
{
+ struct input_dev *input_dev = dev->input;
int x, y;

- /* Cannot sleep. Try nonblockingly. If we fail, try again later. */
- if (mutex_trylock(&hdaps_mtx)) {
- mod_timer(&hdaps_timer,jiffies + HDAPS_POLL_PERIOD);
- return;
- }
+ mutex_lock(&hdaps_mtx);

if (__hdaps_read_pair(HDAPS_PORT_XPOS, HDAPS_PORT_YPOS, &x, &y))
goto out;

- input_report_abs(hdaps_idev, ABS_X, x - rest_x);
- input_report_abs(hdaps_idev, ABS_Y, y - rest_y);
- input_sync(hdaps_idev);
-
- mod_timer(&hdaps_timer, jiffies + HDAPS_POLL_PERIOD);
+ input_report_abs(input_dev, ABS_X, x - rest_x);
+ input_report_abs(input_dev, ABS_Y, y - rest_y);
+ input_sync(input_dev);

out:
mutex_unlock(&hdaps_mtx);
@@ -536,6 +530,7 @@ static struct dmi_system_id __initdata h

static int __init hdaps_init(void)
{
+ struct input_dev *idev;
int ret;

if (!dmi_check_system(hdaps_whitelist)) {
@@ -563,39 +558,37 @@ static int __init hdaps_init(void)
if (ret)
goto out_device;

- hdaps_idev = input_allocate_device();
+ hdaps_idev = input_allocate_polled_device();
if (!hdaps_idev) {
ret = -ENOMEM;
goto out_group;
}

+ hdaps_idev->poll = hdaps_mousedev_poll;
+ hdaps_idev->poll_interval = HDAPS_POLL_INTERVAL;
+
/* initial calibrate for the input device */
hdaps_calibrate();

/* initialize the input class */
- hdaps_idev->name = "hdaps";
- hdaps_idev->dev.parent = &pdev->dev;
- hdaps_idev->evbit[0] = BIT(EV_ABS);
- input_set_abs_params(hdaps_idev, ABS_X,
+ idev = hdaps_idev->input;
+ idev->name = "hdaps";
+ idev->dev.parent = &pdev->dev;
+ idev->evbit[0] = BIT(EV_ABS);
+ input_set_abs_params(idev, ABS_X,
-256, 256, HDAPS_INPUT_FUZZ, HDAPS_INPUT_FLAT);
- input_set_abs_params(hdaps_idev, ABS_Y,
+ input_set_abs_params(idev, ABS_Y,
-256, 256, HDAPS_INPUT_FUZZ, HDAPS_INPUT_FLAT);

- ret = input_register_device(hdaps_idev);
+ ret = input_register_polled_device(hdaps_idev);
if (ret)
goto out_idev;

- /* start up our timer for the input device */
- init_timer(&hdaps_timer);
- hdaps_timer.function = hdaps_mousedev_poll;
- hdaps_timer.expires = jiffies + HDAPS_POLL_PERIOD;
- add_timer(&hdaps_timer);
-
printk(KERN_INFO "hdaps: driver successfully loaded.\n");
return 0;

out_idev:
- input_free_device(hdaps_idev);
+ input_free_polled_device(hdaps_idev);
out_group:
sysfs_remove_group(&pdev->dev.kobj, &hdaps_attribute_group);
out_device:
@@ -611,8 +604,8 @@ out:

static void __exit hdaps_exit(void)
{
- del_timer_sync(&hdaps_timer);
- input_unregister_device(hdaps_idev);
+ input_unregister_polled_device(hdaps_idev);
+ input_free_polled_device(hdaps_idev);
sysfs_remove_group(&pdev->dev.kobj, &hdaps_attribute_group);
platform_device_unregister(pdev);
platform_driver_unregister(&hdaps_driver);