The patch below does not apply to the 3.12-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable@xxxxxxxxxxxxxxx>. thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From f244d8b623dae7a7bc695b0336f67729b95a9736 Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" <rafael.j.wysocki@xxxxxxxxx> Date: Tue, 31 Dec 2013 13:39:42 +0100 Subject: [PATCH] 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 <mike@xxxxxxxxxxxxxx> Reported-and-tested-by: <madcatx@xxxxxxxx> Reported-and-tested-by: Joaquín Aramendía <samsagax@xxxxxxxxx> Cc: Alex Deucher <alexdeucher@xxxxxxxxx> Cc: Dave Airlie <airlied@xxxxxxxx> Cc: Takashi Iwai <tiwai@xxxxxxx> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@xxxxxxxxx> Cc: 3.12+ <stable@xxxxxxxxxxxxxxx> # 3.12+ diff --git a/drivers/acpi/bus.c b/drivers/acpi/bus.c index bba9b72e25f8..0710004055c8 100644 --- a/drivers/acpi/bus.c +++ b/drivers/acpi/bus.c @@ -156,6 +156,16 @@ int acpi_bus_get_private_data(acpi_handle handle, void **data) } EXPORT_SYMBOL(acpi_bus_get_private_data); +void acpi_bus_no_hotplug(acpi_handle handle) +{ + struct acpi_device *adev = NULL; + + acpi_bus_get_device(handle, &adev); + if (adev) + adev->flags.no_hotplug = true; +} +EXPORT_SYMBOL_GPL(acpi_bus_no_hotplug); + static void acpi_print_osc_error(acpi_handle handle, struct acpi_osc_context *context, char *error) { diff --git a/drivers/gpu/drm/nouveau/nouveau_acpi.c b/drivers/gpu/drm/nouveau/nouveau_acpi.c index 95c740454049..ba0183fb84f3 100644 --- a/drivers/gpu/drm/nouveau/nouveau_acpi.c +++ b/drivers/gpu/drm/nouveau/nouveau_acpi.c @@ -51,6 +51,7 @@ static struct nouveau_dsm_priv { bool dsm_detected; bool optimus_detected; acpi_handle dhandle; + acpi_handle other_handle; acpi_handle rom_handle; } nouveau_dsm_priv; @@ -260,9 +261,10 @@ static int nouveau_dsm_pci_probe(struct pci_dev *pdev) if (!dhandle) return false; - if (!acpi_has_method(dhandle, "_DSM")) + if (!acpi_has_method(dhandle, "_DSM")) { + nouveau_dsm_priv.other_handle = dhandle; return false; - + } if (nouveau_test_dsm(dhandle, nouveau_dsm, NOUVEAU_DSM_POWER)) retval |= NOUVEAU_DSM_HAS_MUX; @@ -338,6 +340,16 @@ static bool nouveau_dsm_detect(void) printk(KERN_INFO "VGA switcheroo: detected DSM switching method %s handle\n", acpi_method_name); nouveau_dsm_priv.dsm_detected = true; + /* + * On some systems hotplug events are generated for the device + * being switched off when _DSM is executed. They cause ACPI + * hotplug to trigger and attempt to remove the device from + * the system, which causes it to break down. Prevent that from + * happening by setting the no_hotplug flag for the involved + * ACPI device objects. + */ + acpi_bus_no_hotplug(nouveau_dsm_priv.dhandle); + acpi_bus_no_hotplug(nouveau_dsm_priv.other_handle); ret = true; } diff --git a/drivers/gpu/drm/radeon/radeon_atpx_handler.c b/drivers/gpu/drm/radeon/radeon_atpx_handler.c index 9d302eaeea15..485848f889f5 100644 --- a/drivers/gpu/drm/radeon/radeon_atpx_handler.c +++ b/drivers/gpu/drm/radeon/radeon_atpx_handler.c @@ -33,6 +33,7 @@ static struct radeon_atpx_priv { bool atpx_detected; /* handle for device - and atpx */ acpi_handle dhandle; + acpi_handle other_handle; struct radeon_atpx atpx; } radeon_atpx_priv; @@ -451,9 +452,10 @@ static bool radeon_atpx_pci_probe_handle(struct pci_dev *pdev) return false; status = acpi_get_handle(dhandle, "ATPX", &atpx_handle); - if (ACPI_FAILURE(status)) + if (ACPI_FAILURE(status)) { + radeon_atpx_priv.other_handle = dhandle; return false; - + } radeon_atpx_priv.dhandle = dhandle; radeon_atpx_priv.atpx.handle = atpx_handle; return true; @@ -530,6 +532,16 @@ static bool radeon_atpx_detect(void) printk(KERN_INFO "VGA switcheroo: detected switching method %s handle\n", acpi_method_name); radeon_atpx_priv.atpx_detected = true; + /* + * On some systems hotplug events are generated for the device + * being switched off when ATPX is executed. They cause ACPI + * hotplug to trigger and attempt to remove the device from + * the system, which causes it to break down. Prevent that from + * happening by setting the no_hotplug flag for the involved + * ACPI device objects. + */ + acpi_bus_no_hotplug(radeon_atpx_priv.dhandle); + acpi_bus_no_hotplug(radeon_atpx_priv.other_handle); return true; } return false; diff --git a/drivers/pci/hotplug/acpiphp_glue.c b/drivers/pci/hotplug/acpiphp_glue.c index 438a4d09958b..e86439283a5d 100644 --- a/drivers/pci/hotplug/acpiphp_glue.c +++ b/drivers/pci/hotplug/acpiphp_glue.c @@ -645,6 +645,24 @@ static void disable_slot(struct acpiphp_slot *slot) slot->flags &= (~SLOT_ENABLED); } +static bool acpiphp_no_hotplug(acpi_handle handle) +{ + struct acpi_device *adev = NULL; + + acpi_bus_get_device(handle, &adev); + return adev && adev->flags.no_hotplug; +} + +static bool slot_no_hotplug(struct acpiphp_slot *slot) +{ + struct acpiphp_func *func; + + list_for_each_entry(func, &slot->funcs, sibling) + if (acpiphp_no_hotplug(func_to_handle(func))) + return true; + + return false; +} /** * get_slot_status - get ACPI slot status @@ -703,7 +721,8 @@ static void trim_stale_devices(struct pci_dev *dev) unsigned long long sta; status = acpi_evaluate_integer(handle, "_STA", NULL, &sta); - alive = ACPI_SUCCESS(status) && sta == ACPI_STA_ALL; + alive = (ACPI_SUCCESS(status) && sta == ACPI_STA_ALL) + || acpiphp_no_hotplug(handle); } if (!alive) { u32 v; @@ -743,8 +762,9 @@ static void acpiphp_check_bridge(struct acpiphp_bridge *bridge) struct pci_dev *dev, *tmp; mutex_lock(&slot->crit_sect); - /* wake up all functions */ - if (get_slot_status(slot) == ACPI_STA_ALL) { + if (slot_no_hotplug(slot)) { + ; /* do nothing */ + } else if (get_slot_status(slot) == ACPI_STA_ALL) { /* remove stale devices if any */ list_for_each_entry_safe(dev, tmp, &bus->devices, bus_list) 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 *); -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html