On Mon, Mar 30, 2020 at 12:34 AM Hans de Goede hdegoede@redhat.com wrote:
Since commit fdde0ff8590b ("ACPI: PM: s2idle: Prevent spurious SCIs from waking up the system") the SCI triggering without there being a wakeup cause recognized by the ACPI sleep code will no longer wakeup the system.
This works as intended, but this is a problem for devices where the SCI is shared with another device which is also a wakeup source.
In the past these, from the pov of the ACPI sleep code, spurious SCIs would still cause a wakeup so the wakeup from the device sharing the interrupt would actually wakeup the system. This now no longer works.
This is a problem on e.g. Bay Trail-T and Cherry Trail devices where some peripherals (typically the XHCI controller) can signal a Power Management Event (PME) to the Power Management Controller (PMC) to wakeup the system, this uses the same interrupt as the SCI. These wakeups are handled through a special INT0002 ACPI device which checks for events in the GPE0a_STS for this and takes care of acking the PME so that the shared interrupt stops triggering.
The change to the ACPI sleep code to ignore the spurious SCI, causes the system to no longer wakeup on these PME events. To make things worse this means that the INT0002 device driver interrupt handler will no longer run, causing the PME to not get cleared and resulting in the system hanging. Trying to wakeup the system after such a PME through e.g. the power button no longer works.
Add an acpi_s2idle_register_wake_callback() function which registers a callback to be called from acpi_s2idle_wake() and when the callback returns true, return true from acpi_s2idle_wake().
The INT0002 driver will use this mechanism to check the GPE0a_STS register from acpi_s2idle_wake() and to tell the system to wakeup if a PME is signaled in the register.
Fixes: fdde0ff8590b ("ACPI: PM: s2idle: Prevent spurious SCIs from waking up the system") Cc: 5.4+ stable@vger.kernel.org # 5.4+ Signed-off-by: Hans de Goede hdegoede@redhat.com
I generally agree with the approach, but I would make some, mostly cosmetic, changes.
First off, I'd put the new code into drivers/acpi/wakeup.c.
I'd export one function from there to be called from acpi_s2idle_wake() and the install/uninstall routines for the users.
drivers/acpi/sleep.c | 70 ++++++++++++++++++++++++++++++++++++++++++++ include/linux/acpi.h | 7 +++++ 2 files changed, 77 insertions(+)
diff --git a/drivers/acpi/sleep.c b/drivers/acpi/sleep.c index e5f95922bc21..e360e51afa8e 100644 --- a/drivers/acpi/sleep.c +++ b/drivers/acpi/sleep.c @@ -943,6 +943,65 @@ static struct acpi_scan_handler lps0_handler = { .attach = lps0_device_attach, };
+struct s2idle_wake_callback {
I'd call this acpi_wakeup_handler.
struct list_head list;
list_node?
bool (*function)(void *data);
bool (*wakeup)(void *context)?
void *user_data;
context?
+};
+static LIST_HEAD(s2idle_wake_callback_head); +static DEFINE_MUTEX(s2idle_wake_callback_mutex);
+/*
- Drivers which may share an IRQ with the SCI can use this to register
- a callback which returns true when the device they are managing wants
- to trigger a wakeup.
- */
+int acpi_s2idle_register_wake_callback(
int wake_irq, bool (*function)(void *data), void *user_data)+{
struct s2idle_wake_callback *callback;/** If the device is not sharing its IRQ with the SCI, there is no* need to register the callback.*/if (!acpi_sci_irq_valid() || wake_irq != acpi_sci_irq)return 0;callback = kmalloc(sizeof(*callback), GFP_KERNEL);if (!callback)return -ENOMEM;callback->function = function;callback->user_data = user_data;mutex_lock(&s2idle_wake_callback_mutex);list_add(&callback->list, &s2idle_wake_callback_head);mutex_unlock(&s2idle_wake_callback_mutex);return 0;+} +EXPORT_SYMBOL_GPL(acpi_s2idle_register_wake_callback);
+void acpi_s2idle_unregister_wake_callback(
bool (*function)(void *data), void *user_data)+{
struct s2idle_wake_callback *cb;mutex_lock(&s2idle_wake_callback_mutex);list_for_each_entry(cb, &s2idle_wake_callback_head, list) {if (cb->function == function &&cb->user_data == user_data) {list_del(&cb->list);kfree(cb);break;}}mutex_unlock(&s2idle_wake_callback_mutex);+} +EXPORT_SYMBOL_GPL(acpi_s2idle_unregister_wake_callback);
static int acpi_s2idle_begin(void) { acpi_scan_lock_acquire(); @@ -992,6 +1051,8 @@ static void acpi_s2idle_sync(void)
static bool acpi_s2idle_wake(void) {
struct s2idle_wake_callback *cb;if (!acpi_sci_irq_valid()) return pm_wakeup_pending();@@ -1025,6 +1086,15 @@ static bool acpi_s2idle_wake(void) if (acpi_any_gpe_status_set() && !acpi_ec_dispatch_gpe()) return true;
/** Check callbacks registered by drivers sharing the SCI.* Note no need to lock, nothing else is running.*/list_for_each_entry(cb, &s2idle_wake_callback_head, list) {if (cb->function(cb->user_data))return true;}
AFAICS this needs to be done in acpi_s2idle_restore() too to clear the status bits in case one of these wakeup sources triggers along with a GPE or a fixed event and the other one wins the race.
/* * Cancel the wakeup and process all pending events in case * there are any wakeup ones in there.diff --git a/include/linux/acpi.h b/include/linux/acpi.h index 0f24d701fbdc..9f06e1dc79c1 100644 --- a/include/linux/acpi.h +++ b/include/linux/acpi.h @@ -488,6 +488,13 @@ void __init acpi_nvs_nosave_s3(void); void __init acpi_sleep_no_blacklist(void); #endif /* CONFIG_PM_SLEEP */
+#ifdef CONFIG_ACPI_SYSTEM_POWER_STATES_SUPPORT +int acpi_s2idle_register_wake_callback(
int wake_irq, bool (*function)(void *data), void *user_data);+void acpi_s2idle_unregister_wake_callback(
bool (*function)(void *data), void *user_data);+#endif
struct acpi_osc_context { char *uuid_str; /* UUID string */ int rev; --
Thanks!