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Certain multi-GPU configurations (especially GFX12) may hit data corruption when a DCC-compressed VRAM surface is shared across GPUs using peer-to-peer (P2P) DMA transfers. Such surfaces rely on device-local metadata and cannot be safely accessed through a remote GPU’s page tables. Attempting to import a DCC-enabled surface through P2P leads to incorrect rendering or GPU faults. This change disables P2P for DCC-enabled VRAM buffers that are contiguous and allocated on GFX12+ hardware. In these cases, the importer falls back to the standard system-memory path, avoiding invalid access to compressed surfaces. Future work could consider optional migration (VRAM→System→VRAM) if a performance regression is observed when `attach->peer2peer = false`. Tested on: - Dual RX 9700 XT (Navi4x) setup - GNOME and Wayland compositor scenarios - Confirmed no corruption after disabling P2P under these conditions v2: Remove check TTM_PL_VRAM & TTM_PL_FLAG_CONTIGUOUS. v3: simplify for upsteam and fix ip version check (Alex) Suggested-by: Christian König <christian.koenig@amd.com> Signed-off-by: Vitaly Prosyak <vitaly.prosyak@amd.com> Reviewed-by: Christian König <christian.koenig@amd.com> Signed-off-by: Alex Deucher <alexander.deucher@amd.com> (cherry picked from commit 9dff2bb709e6fbd97e263fd12bf12802d2b5a0cf) Cc: stable@vger.kernel.org
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.