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On most platforms, _LID returning value, lid open/close events are all reliable, but there are exceptions. Some AML tables report wrong initial lid state [1], and some of them never report lid open state [2]. The usage model on such buggy platforms is: 1. The initial lid state returned from _LID is not reliable; 2. The lid open event is not reliable; 3. The lid close event is always reliable, used by the platform firmware to trigger OSPM power saving operations. This usage model is not compliant to the Linux SW_LID model as the Linux userspace is very strict to the reliability of the open events. In order not to trigger issues on such buggy platforms, the ACPI button driver currently implements a lid_init_state=open quirk to send additional "open" event after resuming. However, this is still not sufficient because: 1. Some special usage models (e.x., the dark resume scenario) cannot be supported by this mode. 2. If a "close" event is not used to trigger "suspend", then the subsequent "close" events cannot be seen by the userspace. So we need to stop sending the additional "open" event and switch the driver to lid_init_state=ignore mode and make sure the platform triggered events can be reliably delivered to the userspace. The userspace programs then can be changed to not to be strict to the "open" events on such buggy platforms. Why will the subsequent "close" events be lost? This is because the input layer automatically filters redundant events for switch events. Thus given that the buggy AML tables do not guarantee paired "open"/"close" events, the ACPI button driver currently is not able to guarantee that the platform triggered reliable events can be always be seen by the userspace via SW_LID. This patch adds a mechanism to insert lid events as a compensation for the platform triggered ones to form a complete event switches in order to make sure that the platform triggered events can always be reliably delivered to the userspace. This essentially guarantees that the platform triggered reliable "close" events will always be relibly delivered to the userspace. However this mechanism is not suitable for lid_init_state=open/method as it should not send the complement switch event for the unreliable initial lid state notification. 2 unreliable events can trigger unexpected behavior. Thus this patch only implements this mechanism for lid_init_state=ignore. Known issues: 1. Possible alternative approach This approach is based on the fact that Linux requires a switch event type for LID events. Another approach is to use key event type to implement ACPI lid events. With SW event type, since ACPI button driver inserts wrong lid events, there could be a potential issue that an "open" event issued from some AML update methods could result in a wrong "close" event to be delivered to the userspace. While using KEY event type, there is no such problem. However there may not be such a kind of real case, and if there is such a case, it is worked around in this patch as the complement switch event is only generated for "close" event in order to deliver the reliable "close" event to the userspace. Link: https://bugzilla.kernel.org/show_bug.cgi?id=89211 # [1] Link: https://bugzilla.kernel.org/show_bug.cgi?id=106151 # [1] Link: https://bugzilla.kernel.org/show_bug.cgi?id=106941 # [2] Signed-off-by: Lv Zheng <lv.zheng@intel.com> Suggested-by: Dmitry Torokhov <dmitry.torokhov@gmail.com> Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com> |
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| .. | ||
| acpica | ||
| apei | ||
| dptf | ||
| nfit | ||
| pmic | ||
| ac.c | ||
| acpi_amba.c | ||
| acpi_apd.c | ||
| acpi_cmos_rtc.c | ||
| acpi_configfs.c | ||
| acpi_dbg.c | ||
| acpi_extlog.c | ||
| acpi_ipmi.c | ||
| acpi_lpat.c | ||
| acpi_lpss.c | ||
| acpi_memhotplug.c | ||
| acpi_pad.c | ||
| acpi_platform.c | ||
| acpi_pnp.c | ||
| acpi_processor.c | ||
| acpi_video.c | ||
| battery.c | ||
| battery.h | ||
| bgrt.c | ||
| blacklist.c | ||
| bus.c | ||
| button.c | ||
| cm_sbs.c | ||
| container.c | ||
| cppc_acpi.c | ||
| custom_method.c | ||
| debugfs.c | ||
| device_pm.c | ||
| device_sysfs.c | ||
| dock.c | ||
| ec_sys.c | ||
| ec.c | ||
| event.c | ||
| evged.c | ||
| fan.c | ||
| glue.c | ||
| gsi.c | ||
| hed.c | ||
| internal.h | ||
| ioapic.c | ||
| Kconfig | ||
| Makefile | ||
| numa.c | ||
| nvs.c | ||
| osi.c | ||
| osl.c | ||
| pci_irq.c | ||
| pci_link.c | ||
| pci_mcfg.c | ||
| pci_root.c | ||
| pci_slot.c | ||
| power.c | ||
| proc.c | ||
| processor_core.c | ||
| processor_driver.c | ||
| processor_idle.c | ||
| processor_pdc.c | ||
| processor_perflib.c | ||
| processor_thermal.c | ||
| processor_throttling.c | ||
| property.c | ||
| reboot.c | ||
| resource.c | ||
| sbs.c | ||
| sbshc.c | ||
| sbshc.h | ||
| scan.c | ||
| sleep.c | ||
| sleep.h | ||
| sysfs.c | ||
| tables.c | ||
| thermal.c | ||
| utils.c | ||
| video_detect.c | ||
| wakeup.c | ||