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eeepc-wmi: serialize access to wmi method

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\AMW0.WMBC, which is the main method that we use,
is not reentrant. When wireless hotpluging is enabled,
toggling the status of the wireless device using WMBC will
trigger a notification and the notification handler need to
call WMBC again to get the new status of the device, this
will trigger the following error:

ACPI Error (dswload-0802): [_T_0] Namespace lookup failure, AE_ALREADY_EXISTS
ACPI Exception: AE_ALREADY_EXISTS, During name lookup/catalog (20100428/psloop-231)
ACPI Error (psparse-0537): Method parse/execution failed [\AMW0.WMBC] (Node f7023b88), AE_ALREADY_EXISTS
ACPI: Marking method WMBC as Serialized because of AE_ALREADY_EXISTS error

Since there is currently no way to tell the acpi subsystem to mark
a method as serialized, we do it in eeepc-wmi.

Of course, we could let the first call fail, and then it would work,
but it doesn't seems really clean, and it will make the first
WMBC call return a random value.

This patch was tested on EeePc 1000H with a RaLink RT2860
wireless card using the rt2800pci driver. rt2860sta driver
seems to deadlock when we remove the pci device...

Signed-off-by: Corentin Chary <corentincj@iksaif.net>
Signed-off-by: Matthew Garrett <mjg@redhat.com>
This commit is contained in:
Corentin Chary 2011-02-06 13:28:29 +01:00 committed by Matthew Garrett
parent afa7c88657
commit 279f8f9549
1 changed files with 72 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

78
drivers/platform/x86/eeepc-wmi.c
View File

@ -137,6 +137,9 @@ struct eeepc_wmi {
struct hotplug_slot *hotplug_slot;
struct mutex hotplug_lock;
struct mutex wmi_lock;
struct workqueue_struct *hotplug_workqueue;
struct work_struct hotplug_work;
struct eeepc_wmi_debug debug;
};
@ -370,15 +373,19 @@ static void eeepc_rfkill_hotplug(struct eeepc_wmi *eeepc)
{
struct pci_dev *dev;
struct pci_bus *bus;
bool blocked = eeepc_wlan_rfkill_blocked(eeepc);
bool blocked;
bool absent;
u32 l;
if (eeepc->wlan_rfkill)
rfkill_set_sw_state(eeepc->wlan_rfkill, blocked);
mutex_lock(&eeepc->wmi_lock);
blocked = eeepc_wlan_rfkill_blocked(eeepc);
mutex_unlock(&eeepc->wmi_lock);
mutex_lock(&eeepc->hotplug_lock);
if (eeepc->wlan_rfkill)
rfkill_set_sw_state(eeepc->wlan_rfkill, blocked);
if (eeepc->hotplug_slot) {
bus = pci_find_bus(0, 1);
if (!bus) {
@ -435,7 +442,14 @@ static void eeepc_rfkill_notify(acpi_handle handle, u32 event, void *data)
if (event != ACPI_NOTIFY_BUS_CHECK)
return;
eeepc_rfkill_hotplug(eeepc);
/*
* We can't call directly eeepc_rfkill_hotplug because most
* of the time WMBC is still being executed and not reetrant.
* There is currently no way to tell ACPICA that we want this
* method to be serialized, we schedule a eeepc_rfkill_hotplug
* call later, in a safer context.
*/
queue_work(eeepc->hotplug_workqueue, &eeepc->hotplug_work);
}
static int eeepc_register_rfkill_notifier(struct eeepc_wmi *eeepc,
@ -508,6 +522,14 @@ static struct hotplug_slot_ops eeepc_hotplug_slot_ops = {
.get_power_status = eeepc_get_adapter_status,
};
static void eeepc_hotplug_work(struct work_struct *work)
{
struct eeepc_wmi *eeepc;
eeepc = container_of(work, struct eeepc_wmi, hotplug_work);
eeepc_rfkill_hotplug(eeepc);
}
static int eeepc_setup_pci_hotplug(struct eeepc_wmi *eeepc)
{
int ret = -ENOMEM;
@ -518,6 +540,13 @@ static int eeepc_setup_pci_hotplug(struct eeepc_wmi *eeepc)
return -ENODEV;
}
eeepc->hotplug_workqueue =
create_singlethread_workqueue("hotplug_workqueue");
if (!eeepc->hotplug_workqueue)
goto error_workqueue;
INIT_WORK(&eeepc->hotplug_work, eeepc_hotplug_work);
eeepc->hotplug_slot = kzalloc(sizeof(struct hotplug_slot), GFP_KERNEL);
if (!eeepc->hotplug_slot)
goto error_slot;
@ -547,6 +576,8 @@ error_info:
kfree(eeepc->hotplug_slot);
eeepc->hotplug_slot = NULL;
error_slot:
destroy_workqueue(eeepc->hotplug_workqueue);
error_workqueue:
return ret;
}
@ -575,6 +606,34 @@ static void eeepc_rfkill_query(struct rfkill *rfkill, void *data)
rfkill_set_sw_state(rfkill, !(retval & 0x1));
}
static int eeepc_rfkill_wlan_set(void *data, bool blocked)
{
struct eeepc_wmi *eeepc = data;
int ret;
/*
* This handler is enabled only if hotplug is enabled.
* In this case, the eeepc_wmi_set_devstate() will
* trigger a wmi notification and we need to wait
* this call to finish before being able to call
* any wmi method
*/
mutex_lock(&eeepc->wmi_lock);
ret = eeepc_rfkill_set((void *)(long)EEEPC_WMI_DEVID_WLAN, blocked);
mutex_unlock(&eeepc->wmi_lock);
return ret;
}
static void eeepc_rfkill_wlan_query(struct rfkill *rfkill, void *data)
{
eeepc_rfkill_query(rfkill, (void *)(long)EEEPC_WMI_DEVID_WLAN);
}
static const struct rfkill_ops eeepc_rfkill_wlan_ops = {
.set_block = eeepc_rfkill_wlan_set,
.query = eeepc_rfkill_wlan_query,
};
static const struct rfkill_ops eeepc_rfkill_ops = {
.set_block = eeepc_rfkill_set,
.query = eeepc_rfkill_query,
@ -603,8 +662,12 @@ static int eeepc_new_rfkill(struct eeepc_wmi *eeepc,
if (!retval || retval == 0x00060000)
return -ENODEV;
*rfkill = rfkill_alloc(name, &eeepc->platform_device->dev, type,
&eeepc_rfkill_ops, (void *)(long)dev_id);
if (dev_id == EEEPC_WMI_DEVID_WLAN && eeepc->hotplug_wireless)
*rfkill = rfkill_alloc(name, &eeepc->platform_device->dev, type,
&eeepc_rfkill_wlan_ops, eeepc);
else
*rfkill = rfkill_alloc(name, &eeepc->platform_device->dev, type,
&eeepc_rfkill_ops, (void *)(long)dev_id);
if (!*rfkill)
return -EINVAL;
@ -636,6 +699,8 @@ static void eeepc_wmi_rfkill_exit(struct eeepc_wmi *eeepc)
eeepc_rfkill_hotplug(eeepc);
if (eeepc->hotplug_slot)
pci_hp_deregister(eeepc->hotplug_slot);
if (eeepc->hotplug_workqueue)
destroy_workqueue(eeepc->hotplug_workqueue);
if (eeepc->bluetooth_rfkill) {
rfkill_unregister(eeepc->bluetooth_rfkill);
@ -654,6 +719,7 @@ static int eeepc_wmi_rfkill_init(struct eeepc_wmi *eeepc)
int result = 0;
mutex_init(&eeepc->hotplug_lock);
mutex_init(&eeepc->wmi_lock);
result = eeepc_new_rfkill(eeepc, &eeepc->wlan_rfkill,
"eeepc-wlan", RFKILL_TYPE_WLAN,