From f244d8b623dae7a7bc695b0336f67729b95a9736 Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Tue, 31 Dec 2013 13:39:42 +0100 Subject: ACPIPHP / radeon / nouveau: Fix VGA switcheroo problem related to hotplug MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit The changes in the ACPI-based PCI hotplug (ACPIPHP) subsystem made during the 3.12 development cycle uncovered a problem with VGA switcheroo that on some systems, when the device-specific method (ATPX in the radeon case, _DSM in the nouveau case) is used to turn off the discrete graphics, the BIOS generates ACPI hotplug events for that device and those events cause ACPIPHP to attempt to remove the device from the system (they are events for a device that was present previously and is not present any more, so that's what should be done according to the spec). Then, the system stops functioning correctly. Since the hotplug events in question were simply silently ignored previously, the least intrusive way to address that problem is to make ACPIPHP ignore them again. For this purpose, introduce a new ACPI device flag, no_hotplug, and modify ACPIPHP to ignore hotplug events for PCI devices whose ACPI companions have that flag set. Next, make the radeon and nouveau switcheroo detection code set the no_hotplug flag for the discrete graphics' ACPI companion. Fixes: bbd34fcdd1b2 (ACPI / hotplug / PCI: Register all devices under the given bridge) References: https://bugzilla.kernel.org/show_bug.cgi?id=61891 References: https://bugzilla.kernel.org/show_bug.cgi?id=64891 Reported-and-tested-by: Mike Lothian Reported-and-tested-by: Reported-and-tested-by: Joaquín Aramendía Cc: Alex Deucher Cc: Dave Airlie Cc: Takashi Iwai Signed-off-by: Rafael J. Wysocki Cc: 3.12+ # 3.12+ --- include/acpi/acpi_bus.h | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'include') diff --git a/include/acpi/acpi_bus.h b/include/acpi/acpi_bus.h index 7b2de026a4f3..ca49ebd231ca 100644 --- a/include/acpi/acpi_bus.h +++ b/include/acpi/acpi_bus.h @@ -168,7 +168,8 @@ struct acpi_device_flags { u32 ejectable:1; u32 power_manageable:1; u32 match_driver:1; - u32 reserved:27; + u32 no_hotplug:1; + u32 reserved:26; }; /* File System */ @@ -343,6 +344,7 @@ extern struct kobject *acpi_kobj; extern int acpi_bus_generate_netlink_event(const char*, const char*, u8, int); void acpi_bus_private_data_handler(acpi_handle, void *); int acpi_bus_get_private_data(acpi_handle, void **); +void acpi_bus_no_hotplug(acpi_handle handle); extern int acpi_notifier_call_chain(struct acpi_device *, u32, u32); extern int register_acpi_notifier(struct notifier_block *); extern int unregister_acpi_notifier(struct notifier_block *); -- cgit v1.2.3