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dma_fence_wait_timeout returns a long type but the driver is only using the lower 32 bits of the retval and discarding the upper 32 bits. This is particularly problematic if there are already signalled or stub fences on some of the hw planes. In this case the dma_fence_wait_timeout function will immediately return with timeout value MAX_SCHEDULE_TIMEOUT (0x7fffffffffffffff) since the fence is already signalled. If the driver only uses the lower 32 bits of this return value then it'll interpret it as an error code (0xFFFFFFFF or (-1)) and skip the wait on the remaining fences. This issue was first observed in the xe driver with the Android compositor where the GPU composited layer was not properly waited on when there were stub fences in other overlay planes resulting in visual artifacts. Fixes:d59cf7bb73("drm/i915/display: Use dma_fence interfaces instead of i915_sw_fence") Signed-off-by: Aakash Deep Sarkar <aakash.deep.sarkar@intel.com> Reviewed-by: Matthew Brost <matthew.brost@intel.com> Signed-off-by: Ankit Nautiyal <ankit.k.nautiyal@intel.com> Link: https://lore.kernel.org/r/20250708074540.1948068-1-aakash.deep.sarkar@intel.com (cherry picked from commitcdb1603951) Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
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.