Linux kernel modifications for the Kernel Hacking exam
f2fa5a99ca
Replace GEM VRAM helpers with GEM SHMEM helpers in ast. Avoids OOM errors when allocating video memory. Also adds support for dma-buf functionality. Aspeed display hardware supports display resolutions of FullHD and higher at 32-bit pixel depth. But the amount of video memory is in the range of 8 MiB to 32 MiB, which adds constraints to the actually available resolutions. As atomic modesetting with VRAM helpers requires double buffering in video memory, ast fails to pageflip in some configurations. For example, FullHD with an active cursor plane does not work on devices with 16 MiB of video memory. Resolve this problem by converting the ast driver to GEM SHMEM helpers. Keep the buffer objects in system memory and copy to video memory on pageflips via shadow-plane helpers. Userspace used to require shadow planes for decent performance, but that's now provided by the driver. To replace the memory management, the patch also implements damage handling for the primary plane. With GEM SHMEM helpers, dma-buf import and export is now supported by ast. This allows easier screen mirroring across devices or with an Aspeed-based BMC. A corresponding feature request is available at [1]. v2: * fix typos in commit message (Jocelyn) Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de> Reviewed-by: Jocelyn Falempe <jfalempe@redhat.com> Tested-by: Jocelyn Falempe <jfalempe@redhat.com> Link: https://lore.kernel.org/dri-devel/20220901124451.2523077-1-oushixiong@kylinos.cn/ # [1] Link: https://patchwork.freedesktop.org/patch/msgid/20221013112923.769-8-tzimmermann@suse.de |
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| arch | ||
| block | ||
| certs | ||
| crypto | ||
| Documentation | ||
| drivers | ||
| fs | ||
| include | ||
| init | ||
| io_uring | ||
| ipc | ||
| kernel | ||
| lib | ||
| LICENSES | ||
| mm | ||
| net | ||
| samples | ||
| scripts | ||
| security | ||
| sound | ||
| tools | ||
| usr | ||
| virt | ||
| .clang-format | ||
| .cocciconfig | ||
| .get_maintainer.ignore | ||
| .gitattributes | ||
| .gitignore | ||
| .mailmap | ||
| COPYING | ||
| CREDITS | ||
| Kbuild | ||
| Kconfig | ||
| MAINTAINERS | ||
| Makefile | ||
| 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 Restructured Text 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.