Daniel Vetter
45d9c8dde4
Aside from deleting lots of code the real motivation here is to switch
the mmap over to VM_PFNMAP, to be more consistent with what real gpu
drivers do. They're all VM_PFNMAP, which means get_user_pages doesn't
work, and even if you try and there's a struct page behind that,
touching it and mucking around with its refcount can upset drivers
real bad.
v2: Review from Thomas:
- sort #include
- drop more dead code that I didn't spot somehow
v3: select DRM_GEM_SHMEM_HELPER to make it build (intel-gfx-ci)
v4: I got tricked by 0cf2ef46c6 ("drm/shmem-helper: Use cached
mappings by default"), and we need WC in vgem because vgem doesn't
have explicit begin/end cpu access ioctls.
Also add a comment why exactly vgem has to use wc.
v5: Don't set obj->base.funcs, it will default to drm_gem_shmem_funcs
(Thomas)
v6: vgem also needs an MMU for remapping
v7: I absolutely butchered the rebases over the vgem mmap change and
revert and broke the patch. Actually go back to v6 from before the
vgem mmap changes.
Cc: Thomas Zimmermann <tzimmermann@suse.de>
Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Cc: "Christian König" <christian.koenig@amd.com>
Signed-off-by: Daniel Vetter <daniel.vetter@intel.com>
Cc: Melissa Wen <melissa.srw@gmail.com>
Cc: Chris Wilson <chris@chris-wilson.co.uk>
Link: https://patchwork.freedesktop.org/patch/msgid/20210812131412.2487363-4-daniel.vetter@ffwll.ch
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.