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The Lenovo Yoga Book 9 14IAH10 (83KJ) (17EF:6161) firmware includes a HID_DG_TOUCHPAD application collection designed for the Windows inbox HID driver's Win8 PTP touchpad mode. On Linux the HID_DG_TOUCHSCREEN collections provide the correct direct-touch interface. The presence of the touchpad collection causes hid-multitouch to misclassify the touchscreen nodes as indirect buttonpads, leaving them non-functional. Within the touchpad collection: - HID_UP_BUTTON usages trigger the touchscreen-with-buttons heuristic that sets INPUT_MT_POINTER on the touchscreen applications. - The HID_DG_TOUCHPAD application itself sets INPUT_MT_POINTER via mt_allocate_application(), propagating to all touchscreen nodes. - A HID_DG_BUTTONTYPE feature (report 0x51) returns MT_BUTTONTYPE_CLICKPAD, setting td->is_buttonpad = true for the entire device. Additionally, the firmware resets if any USB control request arrives while the CDC-ACM interface is initialising (~1.18 s after enumeration). The Win8 compliance blob (0xff00:0xc5) and Contact Count Max feature reports in the touchscreen collections trigger GET_REPORT calls at probe that hit this window. Surface Switch (0x57) and Button Switch (0x58) feature reports are sent by mt_set_modes() on every input-device open and close, repeatedly hitting this window throughout device lifetime. The firmware also leaves a persistent ghost contact in its contact buffer (contact ID 2, fixed coordinates, tip always asserted) on every enumeration. This ghost occupies a multitouch slot and prevents KWin from seeing a clean finger-lift, causing stuck touch state. The ghost is cleared when Input Mode is set via HID_REQ_SET_REPORT at probe. Fix using a report descriptor fixup in mt_report_fixup() and a class definition update: 1. Remove the entire HID_DG_TOUCHPAD application collection. Parsing HID short items from its header to the matching End Collection and closing the gap with memmove eliminates all three BUTTONPAD heuristics and the feature reports within the collection. 2. Neutralize the Win8 compliance blob feature reports remaining in the touchscreen collections by changing Usage Page 0xff00 to 0x0f00, preventing the case 0xff0000c5 branch in mt_feature_mapping() from issuing GET_REPORT. 3. Neutralize the Contact Count Max feature reports by changing usage 0x55 to 0x00; set maxcontacts = 10 in the class definition so the driver uses the correct contact limit without querying the device. 4. Neutralize Surface Switch (0x57) and Button Switch (0x58) feature report usages in the Device Configuration collection so mt_set_modes() does not issue HID_REQ_SET_REPORT for these on every input-device open/close. Input Mode (0x52) is intentionally left intact: the single HID_REQ_SET_REPORT at probe flushes the firmware's contact buffer and clears the persistent ghost contact. By probe time the cdc-acm driver has already satisfied the CDC-ACM init watchdog (~130 ms), so this request arrives safely after the reset window has closed. 5. Add MT_QUIRK_NOT_SEEN_MEANS_UP to the MT_CLS_YOGABOOK9I class so that contacts not present in a frame are released via INPUT_MT_DROP_UNUSED, preventing stale multitouch slots from lingering if the firmware omits a contact from a report. Signed-off-by: Dave Carey <carvsdriver@gmail.com> Tested-by: Dave Carey <carvsdriver@gmail.com> Signed-off-by: Jiri Kosina <jkosina@suse.com> |
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Linux kernel ============ The Linux kernel is the core of any Linux operating system. It manages hardware, system resources, and provides the fundamental services for all other software. Quick Start ----------- * Report a bug: See Documentation/admin-guide/reporting-issues.rst * Get the latest kernel: https://kernel.org * Build the kernel: See Documentation/admin-guide/quickly-build-trimmed-linux.rst * Join the community: https://lore.kernel.org/ Essential Documentation ----------------------- All users should be familiar with: * Building requirements: Documentation/process/changes.rst * Code of Conduct: Documentation/process/code-of-conduct.rst * License: See COPYING Documentation can be built with make htmldocs or viewed online at: https://www.kernel.org/doc/html/latest/ Who Are You? ============ Find your role below: * New Kernel Developer - Getting started with kernel development * Academic Researcher - Studying kernel internals and architecture * Security Expert - Hardening and vulnerability analysis * Backport/Maintenance Engineer - Maintaining stable kernels * System Administrator - Configuring and troubleshooting * Maintainer - Leading subsystems and reviewing patches * Hardware Vendor - Writing drivers for new hardware * Distribution Maintainer - Packaging kernels for distros * AI Coding Assistant - LLMs and AI-powered development tools For Specific Users ================== New Kernel Developer -------------------- Welcome! Start your kernel development journey here: * Getting Started: Documentation/process/development-process.rst * Your First Patch: Documentation/process/submitting-patches.rst * Coding Style: Documentation/process/coding-style.rst * Build System: Documentation/kbuild/index.rst * Development Tools: Documentation/dev-tools/index.rst * Kernel Hacking Guide: Documentation/kernel-hacking/hacking.rst * Core APIs: Documentation/core-api/index.rst Academic Researcher ------------------- Explore the kernel's architecture and internals: * Researcher Guidelines: Documentation/process/researcher-guidelines.rst * Memory Management: Documentation/mm/index.rst * Scheduler: Documentation/scheduler/index.rst * Networking Stack: Documentation/networking/index.rst * Filesystems: Documentation/filesystems/index.rst * RCU (Read-Copy Update): Documentation/RCU/index.rst * Locking Primitives: Documentation/locking/index.rst * Power Management: Documentation/power/index.rst Security Expert --------------- Security documentation and hardening guides: * Security Documentation: Documentation/security/index.rst * LSM Development: Documentation/security/lsm-development.rst * Self Protection: Documentation/security/self-protection.rst * Reporting Vulnerabilities: Documentation/process/security-bugs.rst * CVE Procedures: Documentation/process/cve.rst * Embargoed Hardware Issues: Documentation/process/embargoed-hardware-issues.rst * Security Features: Documentation/userspace-api/seccomp_filter.rst Backport/Maintenance Engineer ----------------------------- Maintain and stabilize kernel versions: * Stable Kernel Rules: Documentation/process/stable-kernel-rules.rst * Backporting Guide: Documentation/process/backporting.rst * Applying Patches: Documentation/process/applying-patches.rst * Subsystem Profile: Documentation/maintainer/maintainer-entry-profile.rst * Git for Maintainers: Documentation/maintainer/configure-git.rst System Administrator -------------------- Configure, tune, and troubleshoot Linux systems: * Admin Guide: Documentation/admin-guide/index.rst * Kernel Parameters: Documentation/admin-guide/kernel-parameters.rst * Sysctl Tuning: Documentation/admin-guide/sysctl/index.rst * Tracing/Debugging: Documentation/trace/index.rst * Performance Security: Documentation/admin-guide/perf-security.rst * Hardware Monitoring: Documentation/hwmon/index.rst Maintainer ---------- Lead kernel subsystems and manage contributions: * Maintainer Handbook: Documentation/maintainer/index.rst * Pull Requests: Documentation/maintainer/pull-requests.rst * Managing Patches: Documentation/maintainer/modifying-patches.rst * Rebasing and Merging: Documentation/maintainer/rebasing-and-merging.rst * Development Process: Documentation/process/maintainer-handbooks.rst * Maintainer Entry Profile: Documentation/maintainer/maintainer-entry-profile.rst * Git Configuration: Documentation/maintainer/configure-git.rst Hardware Vendor --------------- Write drivers and support new hardware: * Driver API Guide: Documentation/driver-api/index.rst * Driver Model: Documentation/driver-api/driver-model/driver.rst * Device Drivers: Documentation/driver-api/infrastructure.rst * Bus Types: Documentation/driver-api/driver-model/bus.rst * Device Tree Bindings: Documentation/devicetree/bindings/ * Power Management: Documentation/driver-api/pm/index.rst * DMA API: Documentation/core-api/dma-api.rst Distribution Maintainer ----------------------- Package and distribute the kernel: * Stable Kernel Rules: Documentation/process/stable-kernel-rules.rst * ABI Documentation: Documentation/ABI/README * Kernel Configuration: Documentation/kbuild/kconfig.rst * Module Signing: Documentation/admin-guide/module-signing.rst * Kernel Parameters: Documentation/admin-guide/kernel-parameters.rst * Tainted Kernels: Documentation/admin-guide/tainted-kernels.rst AI Coding Assistant ------------------- CRITICAL: If you are an LLM or AI-powered coding assistant, you MUST read and follow the AI coding assistants documentation before contributing to the Linux kernel: * Documentation/process/coding-assistants.rst This documentation contains essential requirements about licensing, attribution, and the Developer Certificate of Origin that all AI tools must comply with. Communication and Support ========================= * Mailing Lists: https://lore.kernel.org/ * IRC: #kernelnewbies on irc.oftc.net * Bugzilla: https://bugzilla.kernel.org/ * MAINTAINERS file: Lists subsystem maintainers and mailing lists * Email Clients: Documentation/process/email-clients.rst