mirror of
https://github.com/torvalds/linux.git
synced 2026-07-28 10:09:10 +02:00
Linux kernel source tree
8382cd2349
[Why]
On DCN, vblank events were delivered from VSTARTUP/VUPDATE
(dm_crtc_high_irq/dm_vupdate_high_irq) and pageflip completion from
GRPH_PFLIP (dm_pflip_high_irq). These signals can be masked by hardware
by a few things:
* DPG - DCN can Dynamically Power Gate parts of the display pipe when a
self-refresh capable eDP is connected. DPG is engaged when there's
enough static frames (detected through drm_vblank_off). Once gated,
even though the OTG (output timing generator) is still enabled,
VSTARTUP and GRPH_FLIP are masked.
* GSL - Driver can use the Global Sync Lock to block HW from latching
onto double-buffered registers during programming, to prevent HW from
latching onto a partially programmed state. This will mask VSTARTUP,
GRPH_FLIP, and VUPDATE. See dcn20_pipe_control_lock().
* MALL - A DCN accessible cache introduced in DCN32+ DGPUs that can
store fb data to allow for longer DRAM sleep. When scanning out from
MALL, VSTARTUP is masked.
When masked, events are never delivered, which can show up as flip_done
timeouts in the wild.
However, there is an interrupt source on DCN that is never masked:
VUPDATE_NO_LOCK. It's simply an unmasked variant of VUPDATE, which fires
while the OTG is active, at the exact point hardware latches
double-buffered registers. It is therefore the natural single signal for
delivering both vblank and flip-completion events on DCN, and the
correct point to timestamp both VRR and non-VRR vblanks.
DCE's interrupt sources are different, it does not have an unmaskable
VUPDATE_NO_LOCK. The only unmaskable DCE interrupt is VLINE0, but it can
only be programmed as a vline offset from vsync_start, making it
unsuitable for VRR. Thus, we keep DCE untouched and use the existing mix
of interrupt sources.
[How]
For DCN1 and newer only:
* Factor the body of dm_crtc_high_irq() into dm_crtc_high_irq_handler()
and drive it from dm_vupdate_high_irq() (VUPDATE_NO_LOCK). DCE keeps
using dm_crtc_high_irq() (VSTARTUP) and dm_pflip_high_irq()
(GRPH_PFLIP) unchanged.
* Stop registering VSTARTUP (crtc_irq) and GRPH_PFLIP (pageflip_irq) on
DCN, and stop enabling them in amdgpu_dm_crtc_set_vblank() /
manage_dm_interrupts(). Enable VUPDATE whenever vblank is enabled on
DCN (previously only in VRR mode). The secure-display vline0 interrupt
is left untouched.
* VUPDATE_NO_LOCK does not early-fire on an immediate (tearing / async)
flip, since HW latches the new address right away. Deliver the flip
completion event immediately after programming such flips in
amdgpu_dm_commit_planes(), and clear pflip_status so the next vupdate
handler does not double-send.
v2: Do not gate VUPDATE_NO_LOCK on DCN in dm_handle_vrr_transition()
Also toggle VUPDATE_NO_LOCK on DCN in dm_gpureset_toggle_interrupts()
Re-cook vblank event count and timestamp for immediate flips
Fixes:
|
||
|---|---|---|
| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| io_uring | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| rust | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .clippy.toml | ||
| .cocciconfig | ||
| .editorconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| .pylintrc | ||
| .rustfmt.toml | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| README | ||
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