Commit b5539eb5 authored by Rafael J. Wysocki's avatar Rafael J. Wysocki
Browse files

ACPI: EC: Fix acpi_ec_dispatch_gpe() 



Commit 896e97bf ("ACPI: EC: Clear GPE on interrupt handling only")
broke suspend-to-idle at least on Dell XPS13 9360 and 9380.

The problem is that acpi_ec_dispatch_gpe() must clear the EC GPE,
because the EC GPE handler never runs when the system is in the
suspend-to-idle state and if the EC GPE is not cleared by the suspend-
to-idle loop, it is never cleared at all which leads to a GPE storm.
This causes suspend-to-idle to burn energy instead of saving it which
is potentially dangerous (the affected machines heat up rather badly
when that happens).

Addess this by making acpi_ec_dispatch_gpe() clear the EC GPE as it did
before.

Fixes: 896e97bf ("ACPI: EC: Clear GPE on interrupt handling only")
Tested-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
parent bb695055

drivers/acpi/ec.c

+12 −6
Original line number Diff line number Diff line
@@ -1267,12 +1267,8 @@ static void acpi_ec_event_handler(struct work_struct *work) 
	spin_unlock_irq(&ec->lock);

}



static void acpi_ec_handle_interrupt(struct acpi_ec *ec)

static void clear_gpe_and_advance_transaction(struct acpi_ec *ec, bool interrupt)

{

	unsigned long flags;



	spin_lock_irqsave(&ec->lock, flags);



	/*

	 * Clear GPE_STS upfront to allow subsequent hardware GPE_STS 0->1

	 * changes to always trigger a GPE interrupt.
@@ -1289,6 +1285,16 @@ static void acpi_ec_handle_interrupt(struct acpi_ec *ec) 
		acpi_clear_gpe(NULL, ec->gpe);



	advance_transaction(ec, true);

}



static void acpi_ec_handle_interrupt(struct acpi_ec *ec)

{

	unsigned long flags;



	spin_lock_irqsave(&ec->lock, flags);



	clear_gpe_and_advance_transaction(ec, true);



	spin_unlock_irqrestore(&ec->lock, flags);

}
@@ -2083,7 +2089,7 @@ bool acpi_ec_dispatch_gpe(void) 
	if (acpi_ec_gpe_status_set(first_ec)) {

		pm_pr_dbg("ACPI EC GPE status set\n");



		advance_transaction(first_ec, false);

		clear_gpe_and_advance_transaction(first_ec, false);

		work_in_progress = acpi_ec_work_in_progress(first_ec);

	}