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Mario Kleiner 557f653991 drm/amd/display: Use same max plane scaling limits for all 64 bpp formats 
[ Upstream commit f0157ce46c ]

The plane scaling hw seems to have the same min/max plane scaling limits
for all 16 bpc / 64 bpp interleaved pixel color formats.

Therefore add cases to amdgpu_dm_plane_get_min_max_dc_plane_scaling() for
all the 16 bpc fixed-point / unorm formats to use the same .fp16
up/downscaling factor limits as used by the fp16 floating point formats.

So far, 16 bpc unorm formats were not handled, and the default: path
returned max/min factors for 32 bpp argb8888 formats, which were wrong
and bigger than what many DCE / DCN hw generations could handle.

The result sometimes was misscaling of framebuffers with
DRM_FORMAT_XRGB16161616, DRM_FORMAT_ARGB16161616, DRM_FORMAT_XBGR16161616,
DRM_FORMAT_ABGR16161616, leading to very wrong looking display, as tested
on Polaris11 / DCE-11.2.

So far this went unnoticed, because only few userspace clients used such
16 bpc unorm framebuffers, and those didn't use hw plane scaling, so they
did not experience this issue.

With upcoming Mesa 26 exposing 16 bpc unorm formats under both OpenGL
and Vulkan under Wayland, and the upcoming GNOME 50 Mutter Wayland
compositor allowing for direct scanout of these formats, the scaling
hw will be used on these formats if possible for HiDPI display scaling,
so it is important to use the correct hw scaling limits to avoid wrong
display.

Tested on AMD Polaris 11 / DCE 11.2 with upcoming Mesa 26 and GNOME 50
on HiDPI displays with scaling enabled. The mutter Wayland compositor now
correctly falls back to scaling via desktop compositing instead of direct
scanout, thereby avoiding wrong image display. For unscaled mode, it
correctly uses direct scanout.

Fixes: 580204038f ("drm/amd/display: Enable support for 16 bpc fixed-point framebuffers.")
Signed-off-by: Mario Kleiner <mario.kleiner.de@gmail.com>
Tested-by: Mario Kleiner <mario.kleiner.de@gmail.com>
Cc: Alex Deucher <alexander.deucher@amd.com>
Cc: Harry Wentland <harry.wentland@amd.com>
Cc: Leo Li <sunpeng.li@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
History 2026-02-26 14:59:44 -08:00
arch x86/hyperv: Fix error pointer dereference 2026-02-26 14:59:44 -08:00
block block,bfq: fix aux stat accumulation destination 2026-02-11 13:41:47 +01:00
certs sign-file,extract-cert: use pkcs11 provider for OPENSSL MAJOR >= 3 2024-09-20 19:52:48 +03:00
crypto crypto: authencesn - reject too-short AAD (assoclen<8) to match ESP/ESN spec 2026-01-30 10:32:12 +01:00
Documentation ipv6: icmp: remove obsolete code in icmpv6_xrlim_allow() 2026-02-26 14:59:40 -08:00
drivers drm/amd/display: Use same max plane scaling limits for all 64 bpp formats 2026-02-26 14:59:44 -08:00
fs btrfs: fix invalid leaf access in btrfs_quota_enable() if ref key not found 2026-02-26 14:59:44 -08:00
include net/mlx5: Fix multiport device check over light SFs 2026-02-26 14:59:40 -08:00
init printk changes for 6.18 2025-10-04 11:13:11 -07:00
io_uring io_uring/cancel: de-unionize file and user_data in struct io_cancel_data 2026-02-26 14:59:36 -08:00
ipc ipc: don't audit capability check in ipc_permissions() 2026-02-26 14:59:19 -08:00
kernel bpf: Add a map/btf from a fd array more consistently 2026-02-26 14:59:38 -08:00
lib objpool: fix the overestimation of object pooling metadata size 2026-02-26 14:59:36 -08:00
LICENSES LICENSES: Replace the obsolete address of the FSF in the GFDL-1.2 2025-07-24 11:15:39 +02:00
mm mm/slab: fix false lockdep warning in __kfree_rcu_sheaf() 2026-02-26 14:59:14 -08:00
net ipv6: icmp: remove obsolete code in icmpv6_xrlim_allow() 2026-02-26 14:59:40 -08:00
rust rust: task: restrict Task::group_leader() to current 2026-02-26 14:59:18 -08:00
samples samples/ftrace: Adjust LoongArch register restore order in direct calls 2026-01-08 10:17:11 +01:00
scripts scripts: generate_rust_analyzer: Add compiler_builtins -> core dep 2026-02-06 16:57:42 +01:00
security apparmor: fix aa_label to return state from compount and component match 2026-02-26 14:59:42 -08:00
sound ASoC: rockchip: i2s-tdm: Use param rate if not provided by set_sysclk 2026-02-26 14:59:44 -08:00
tools selftests: tc_actions: don't dump 2MB of \0 to stdout 2026-02-26 14:59:40 -08:00
usr gen_init_cpio: Ignore fsync() returning EINVAL on pipes 2025-10-07 09:53:05 -07:00
virt KVM: Don't clobber irqfd routing type when deassigning irqfd 2026-02-11 13:41:44 +01:00
.clang-format memblock: drop for_each_free_mem_pfn_range_in_zone_from() 2025-09-14 08:49:03 +03:00
.clippy.toml rust: clean Rust 1.88.0's warning about clippy::disallowed_macros configuration 2025-05-07 00:11:47 +02:00
.cocciconfig scripts: add Linux .cocciconfig for coccinelle 2016-07-22 12:13:39 +02:00
.editorconfig .editorconfig: remove trim_trailing_whitespace option 2024-06-13 16:47:52 +02:00
.get_maintainer.ignore MAINTAINERS: remove Alyssa Rosenzweig 2025-09-18 21:17:31 +02:00
.gitattributes .gitattributes: set diff driver for Rust source code files 2023-05-31 17:48:25 +02:00
.gitignore .gitignore: ignore compile_commands.json globally 2025-08-12 15:53:55 -07:00
.mailmap 8 hotfixes. 4 are cc:stable, 7 are against mm/. 2025-11-26 12:38:05 -08:00
.pylintrc tools: docs: parse-headers.py: move it from sphinx dir 2025-08-29 15:54:42 -06:00
.rustfmt.toml rust: add .rustfmt.toml 2022-09-28 09:02:20 +02:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: mark ISDN subsystem as orphan 2025-10-27 17:49:45 -07:00
Kbuild sched: Make migrate_{en,dis}able() inline 2025-09-25 09:57:16 +02:00
Kconfig io_uring: Rename KConfig to Kconfig 2025-02-19 14:53:27 -07:00
MAINTAINERS soc: fixes for 6.18, part 4 2025-11-28 09:57:31 -08:00
Makefile kbuild: Add objtool to top-level clean target 2026-02-26 14:59:36 -08:00
README README: Fix spelling 2024-03-18 03:36:32 -06:00

README 

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the reStructuredText markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.