linux/drivers/net/wireless/rtl818x/rtl8187_leds.c
Larry Finger 37b12dd2b0 rtl8187: Fix kernel oops when device is removed when LEDS enabled
As reported by Rick Farina (sidhayn@gmail.com), removing the RTL8187
USB stick, or unloading the driver rtl8187 using rmmod will cause a
kernel oops.  There are at least two forms of the failure, (1) BUG:
Scheduling while atomic, and (2) a fatal kernel page fault. This
problem is reported in Bugzilla #14539.

This problem does not occur for kernel 2.6.31, but does for 2.6.32-rc2,
thus it is technically a regression; however, bisection did not locate
any faulty patch. The fix was found by comparing the faulty code in
rtl8187 with p54usb.  My interpretation is that the handling of work
queues in mac80211 changed enough to the LEDs to be unregistered
before tasks on the work queues are cancelled. Previously, these
actions could be done in either order.

(Herton Ronaldo Krzesinski <herton@mandriva.com.br> reports that the
code is the same in 2.6.31, so this may be a candidate for 2.6.31.x.
-- JWL)

Signed-off-by: Larry Finger <Larry.Finger@lwfinger.net>
Reported-by: Rick Farina <sidhayn@gmail.com>
Tested-by: Rick Farina <sidhayn@gmail.com>
Cc: stable@kernel.org
Signed-off-by: John W. Linville <linville@tuxdriver.com>
2009-11-04 19:20:50 -05:00

219 lines
5.9 KiB
C

/*
* Linux LED driver for RTL8187
*
* Copyright 2009 Larry Finger <Larry.Finger@lwfinger.net>
*
* Based on the LED handling in the r8187 driver, which is:
* Copyright (c) Realtek Semiconductor Corp. All rights reserved.
*
* Thanks to Realtek for their support!
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#ifdef CONFIG_RTL8187_LEDS
#include <net/mac80211.h>
#include <linux/usb.h>
#include <linux/eeprom_93cx6.h>
#include "rtl8187.h"
#include "rtl8187_leds.h"
static void led_turn_on(struct work_struct *work)
{
/* As this routine does read/write operations on the hardware, it must
* be run from a work queue.
*/
u8 reg;
struct rtl8187_priv *priv = container_of(work, struct rtl8187_priv,
led_on.work);
struct rtl8187_led *led = &priv->led_tx;
/* Don't change the LED, when the device is down. */
if (priv->mode == NL80211_IFTYPE_UNSPECIFIED)
return ;
/* Skip if the LED is not registered. */
if (!led->dev)
return;
mutex_lock(&priv->conf_mutex);
switch (led->ledpin) {
case LED_PIN_GPIO0:
rtl818x_iowrite8(priv, &priv->map->GPIO0, 0x01);
rtl818x_iowrite8(priv, &priv->map->GP_ENABLE, 0x00);
break;
case LED_PIN_LED0:
reg = rtl818x_ioread8(priv, &priv->map->PGSELECT) & ~(1 << 4);
rtl818x_iowrite8(priv, &priv->map->PGSELECT, reg);
break;
case LED_PIN_LED1:
reg = rtl818x_ioread8(priv, &priv->map->PGSELECT) & ~(1 << 5);
rtl818x_iowrite8(priv, &priv->map->PGSELECT, reg);
break;
case LED_PIN_HW:
default:
break;
}
mutex_unlock(&priv->conf_mutex);
}
static void led_turn_off(struct work_struct *work)
{
/* As this routine does read/write operations on the hardware, it must
* be run from a work queue.
*/
u8 reg;
struct rtl8187_priv *priv = container_of(work, struct rtl8187_priv,
led_off.work);
struct rtl8187_led *led = &priv->led_tx;
/* Don't change the LED, when the device is down. */
if (priv->mode == NL80211_IFTYPE_UNSPECIFIED)
return ;
/* Skip if the LED is not registered. */
if (!led->dev)
return;
mutex_lock(&priv->conf_mutex);
switch (led->ledpin) {
case LED_PIN_GPIO0:
rtl818x_iowrite8(priv, &priv->map->GPIO0, 0x01);
rtl818x_iowrite8(priv, &priv->map->GP_ENABLE, 0x01);
break;
case LED_PIN_LED0:
reg = rtl818x_ioread8(priv, &priv->map->PGSELECT) | (1 << 4);
rtl818x_iowrite8(priv, &priv->map->PGSELECT, reg);
break;
case LED_PIN_LED1:
reg = rtl818x_ioread8(priv, &priv->map->PGSELECT) | (1 << 5);
rtl818x_iowrite8(priv, &priv->map->PGSELECT, reg);
break;
case LED_PIN_HW:
default:
break;
}
mutex_unlock(&priv->conf_mutex);
}
/* Callback from the LED subsystem. */
static void rtl8187_led_brightness_set(struct led_classdev *led_dev,
enum led_brightness brightness)
{
struct rtl8187_led *led = container_of(led_dev, struct rtl8187_led,
led_dev);
struct ieee80211_hw *hw = led->dev;
struct rtl8187_priv *priv = hw->priv;
if (brightness == LED_OFF) {
ieee80211_queue_delayed_work(hw, &priv->led_off, 0);
/* The LED is off for 1/20 sec so that it just blinks. */
ieee80211_queue_delayed_work(hw, &priv->led_on, HZ / 20);
} else
ieee80211_queue_delayed_work(hw, &priv->led_on, 0);
}
static int rtl8187_register_led(struct ieee80211_hw *dev,
struct rtl8187_led *led, const char *name,
const char *default_trigger, u8 ledpin)
{
int err;
struct rtl8187_priv *priv = dev->priv;
if (led->dev)
return -EEXIST;
if (!default_trigger)
return -EINVAL;
led->dev = dev;
led->ledpin = ledpin;
strncpy(led->name, name, sizeof(led->name));
led->led_dev.name = led->name;
led->led_dev.default_trigger = default_trigger;
led->led_dev.brightness_set = rtl8187_led_brightness_set;
err = led_classdev_register(&priv->udev->dev, &led->led_dev);
if (err) {
printk(KERN_INFO "LEDs: Failed to register %s\n", name);
led->dev = NULL;
return err;
}
return 0;
}
static void rtl8187_unregister_led(struct rtl8187_led *led)
{
led_classdev_unregister(&led->led_dev);
led->dev = NULL;
}
void rtl8187_leds_init(struct ieee80211_hw *dev, u16 custid)
{
struct rtl8187_priv *priv = dev->priv;
char name[RTL8187_LED_MAX_NAME_LEN + 1];
u8 ledpin;
int err;
/* According to the vendor driver, the LED operation depends on the
* customer ID encoded in the EEPROM
*/
printk(KERN_INFO "rtl8187: Customer ID is 0x%02X\n", custid);
switch (custid) {
case EEPROM_CID_RSVD0:
case EEPROM_CID_RSVD1:
case EEPROM_CID_SERCOMM_PS:
case EEPROM_CID_QMI:
case EEPROM_CID_DELL:
case EEPROM_CID_TOSHIBA:
ledpin = LED_PIN_GPIO0;
break;
case EEPROM_CID_ALPHA0:
ledpin = LED_PIN_LED0;
break;
case EEPROM_CID_HW:
ledpin = LED_PIN_HW;
break;
default:
ledpin = LED_PIN_GPIO0;
}
INIT_DELAYED_WORK(&priv->led_on, led_turn_on);
INIT_DELAYED_WORK(&priv->led_off, led_turn_off);
snprintf(name, sizeof(name),
"rtl8187-%s::tx", wiphy_name(dev->wiphy));
err = rtl8187_register_led(dev, &priv->led_tx, name,
ieee80211_get_tx_led_name(dev), ledpin);
if (err)
goto error;
snprintf(name, sizeof(name),
"rtl8187-%s::rx", wiphy_name(dev->wiphy));
err = rtl8187_register_led(dev, &priv->led_rx, name,
ieee80211_get_rx_led_name(dev), ledpin);
if (!err) {
ieee80211_queue_delayed_work(dev, &priv->led_on, 0);
return;
}
/* registration of RX LED failed - unregister TX */
rtl8187_unregister_led(&priv->led_tx);
error:
/* If registration of either failed, cancel delayed work */
cancel_delayed_work_sync(&priv->led_off);
cancel_delayed_work_sync(&priv->led_on);
}
void rtl8187_leds_exit(struct ieee80211_hw *dev)
{
struct rtl8187_priv *priv = dev->priv;
/* turn the LED off before exiting */
ieee80211_queue_delayed_work(dev, &priv->led_off, 0);
rtl8187_unregister_led(&priv->led_rx);
rtl8187_unregister_led(&priv->led_tx);
cancel_delayed_work_sync(&priv->led_off);
cancel_delayed_work_sync(&priv->led_on);
}
#endif /* def CONFIG_RTL8187_LED */