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The legacy plane->fb pointer is refcounted by calling drm_atomic_clean_old_fb(). In practice this isn't a real problem because: - The caller in the i915 gpu reset code restores the original state again, which means the plane->fb pointer won't change, hence can't leak. - Drivers using drm_atomic_helper_shutdown call the fbdev cleanup first, and that usually cleans up the fb through drm_remove_framebuffer, which does this correctly. - Without fbdev the only framebuffers are from userspace, and those get cleaned up (again using drm_remove_framebuffer) befor the driver can even be unloaded. But in i915 I've switched the cleanup sequence around so that the _shutdown() calls happens after the drm_remove_framebuffer(), which is how I discovered this issue. v2: My analysis why the current code was ok for gpu reset and suspend/resume was correct, but then I totally failed to realize that we better keep this symmetric. Thanksfully CI noticed that for balance, a refcounting bug must exist at 2 places if previously there was no issue ... v3: Don't be lazy and compute the plane_mask in commit_duplicated_state properly too, instead of just using ~0U. Cc: martin.peres@free.fr Cc: chris@chris-wilson.co.uk Acked-by: Dave Airlie <airlied@gmail.com> (v1) Reviewed-by: Maarten Lankhorst <maarten.lankhorst@linux.intel.com> Signed-off-by: Daniel Vetter <daniel.vetter@intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20170715093106.19873-1-daniel.vetter@ffwll.ch
Linux kernel ============ This file was moved to Documentation/admin-guide/README.rst Please notice that there are several guides for kernel developers and users. These guides can be rendered in a number of formats, like HTML and PDF. In order to build the documentation, use ``make htmldocs`` or ``make pdfdocs``. There are various text files in the Documentation/ subdirectory, several of them using the Restructured Text markup notation. See Documentation/00-INDEX for a list of what is contained in each file. 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.