Pinning lots of small buffer objects, such as cursors or sprites, to video
memory can lead to fragmentation, which is a problem for devices with only
a small amount of memory. As a result, framebuffer images might not get
pinned, even though there's enough space available overall.
The flag DRM_GEM_VRAM_PL_FLAG_TOPDOWN marks buffer objects to be pinned at
the high end of video memory. This leaves contiguous space available at
the memory's low end.
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: https://patchwork.freedesktop.org/patch/msgid/20190923172753.26593-2-tzimmermann@suse.de
Reviewed-by: Gerd Hoffmann <kraxel@redhat.com>
The implementation of vmap and vunmap for GEM VRAM helpers is
already in PRIME helpers. The patch moves the operations to separate
functions and exports them for general use.
v3:
* remove v2's obsolete note on ref-counting
v2:
* fix documentation
* add cross references to function documentation
* document (the lack of) ref-counting for GEM VRAM BO mappings
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Acked-by: Gerd Hoffmann <kraxel@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190911120352.20084-2-tzimmermann@suse.de
The separation between GEM VRAM objects and the memory manager is
artificial, as they are only used with each other. Copying both
implementations into the same file is a first step to simplifying
the code.
This patch only moves code without functional changes.
v3:
* update to use dev->vma_offset_manager
v2:
* update for debugfs support
* typos in commit message
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Acked-by: Gerd Hoffmann <kraxel@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190911110910.30698-2-tzimmermann@suse.de
Wire up drm_mm_print() for vram helpers, using a new
debugfs file, so one can see how vram is used:
# cat /sys/kernel/debug/dri/0/vram-mm
0x0000000000000000-0x0000000000000300: 768: used
0x0000000000000300-0x0000000000000600: 768: used
0x0000000000000600-0x0000000000000900: 768: used
0x0000000000000900-0x0000000000000c00: 768: used
0x0000000000000c00-0x0000000000004000: 13312: free
total: 16384, used 3072 free 13312
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Acked-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: http://patchwork.freedesktop.org/patch/msgid/20190904054740.20817-5-kraxel@redhat.com
The kmap and kunmap operations of GEM VRAM buffers can now be called
in interleaving pairs. The first call to drm_gem_vram_kmap() maps the
buffer's memory to kernel address space and the final call to
drm_gem_vram_kunmap() unmaps the memory. Intermediate calls to these
functions increment or decrement a reference counter.
This change allows for keeping buffer memory mapped for longer and
minimizes the amount of changes to TLB, page tables, etc.
v4:
* lock in kmap()/kunmap() with ttm_bo_reserve()
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Gerd Hoffmann <kraxel@redhat.com>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Reported-and-tested-by: Davidlohr Bueso <dbueso@suse.de>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Link: https://patchwork.freedesktop.org/patch/msgid/20190906122056.32018-2-tzimmermann@suse.de
PRIME functionality is now provided by GEM object functions. The driver
callback functions are obsolete. So this patch renames them and turns
them into static internal functions of the VRAM helper library. The
implementation of gem_prime_mmap is now unused and the patch removes it.
v3:
* kept each renamed function at its original location within file
* kept documentation
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Emil Velikov <emil.velikov@collabora.com>
Reviewed-by: Gerd Hoffmann <kraxel@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190702115012.4418-6-tzimmermann@suse.de
PRIME functionality is now provided via the callback functions in
struct drm_gem_object_funcs. The driver-structure functions are obsolete.
As a side effect of this patch, VRAM-based drivers get basic PRIME
support automatically without having to set any flags or additional
fields.
v2:
- use existing PRIME functions for object's table
v3:
- move object table to EOF so it can refer to internal interfaces
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Emil Velikov <emil.velikov@collabora.com>
Reviewed-by: Gerd Hoffmann <kraxel@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190702115012.4418-2-tzimmermann@suse.de
The push-to-system function forces a buffer out of video RAM. This decision
should rather be made by the memory manager. By replacing the function with
calls to the kunmap and unpin functions, the buffer's memory becomes available,
but the buffer remains in VRAM until it's evicted by a pin operation.
This patch replaces the remaining instances of drm_gem_vram_push_to_system()
in ast and mgag200, and removes the function from DRM.
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/20190521110831.20200-2-tzimmermann@suse.de
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
There's now a pointer to struct drm_vram_mm stored in struct drm_device.
DRM drivers that use VRAM MM should use this field to refer to their
instance of the data structure. Appropriate helpers are now provided as
well.
Adding struct drm_vram_mm to struct drm_device further avoids wrappers
and boilerplate code in drivers. This patch implements default functions
for callbacks in struct drm_driver and struct file_operations that use
the struct drm_vram_mm stored in struct drm_device. Drivers that need to
provide their own implementations can still do so.
The patch also adds documentation for the VRAM helper library in general.
v5:
* set .llseek to no_llseek() from DRM_VRAM_MM_FILE_OPERATIONS
v4:
* cleanups from checkpatch.pl
* document VRAM helper library
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: http://patchwork.freedesktop.org/patch/msgid/20190508082630.15116-9-tzimmermann@suse.de
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
The helper function drm_gem_vram_fill_create_dumb() implements most of
struct drm_driver.dumb_create() for GEM-VRAM buffer objects. It's not a
full implementation of the callback, as several driver-specific parameters
are still required.
v4:
* cleanups from checkpatch.pl
v2:
* documentation fixes
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: http://patchwork.freedesktop.org/patch/msgid/20190508082630.15116-5-tzimmermann@suse.de
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
The type |struct drm_gem_vram_object| implements a GEM object for simple
framebuffer devices with dedicated video memory. The BO is either located
in VRAM or system memory.
The implementation has been created from the respective code in ast,
bochs and mgag200. These drivers copy their implementation from each
other; except for the names of several data types. The helpers are
currently build with TTM, but this is considered an implementation
detail and may change in future updates.
v5:
* do WARN_ON_ONCE for pin-count mismatches
* allocate only 2 entries in placements array
v4:
* cleanups from checkpatch.pl
* removed several fixed-size types from interfaces
* DRM_VRAM_HELPER now selects DRM_TTM
* remove separate config option for GEM VRAM
v2:
* rename to |struct drm_gem_vram_object|
* move drm_is_gem_ttm() to a later patch in the series
* add drm_gem_vram_kmap_at()
* return is_iomem from kmap functions
* redefine TTM placement flags for public interface
* documentation fixes
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Link: http://patchwork.freedesktop.org/patch/msgid/20190508082630.15116-2-tzimmermann@suse.de
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
