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Commit a6c3464f authored by Thomas Zimmermann's avatar Thomas Zimmermann
Browse files

drm/gem-vram: Support pinning buffers to current location 



Pinning a buffer prevents it from being moved to a different memory
location. For some operations, such as buffer updates, it is not
important where the buffer is located. Setting the pin function's
pl_flag argument to 0 will pin the buffer to whereever it is stored.

v2:
	* document pin flags in PRIME pin helper

Signed-off-by: default avatarThomas Zimmermann <tzimmermann@suse.de>
Acked-by: default avatarGerd Hoffmann <kraxel@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190613073041.29350-2-tzimmermann@suse.de
parent bb5ce9a0

drivers/gpu/drm/drm_gem_vram_helper.c

+16 −4
Original line number Diff line number Diff line
@@ -224,7 +224,9 @@ EXPORT_SYMBOL(drm_gem_vram_offset); 
 *

 * Pinning a buffer object ensures that it is not evicted from

 * a memory region. A pinned buffer object has to be unpinned before

 * it can be pinned to another region.

 * it can be pinned to another region. If the pl_flag argument is 0,

 * the buffer is pinned at its current location (video RAM or system

 * memory).

 *

 * Returns:

 * 0 on success, or
@@ -242,7 +244,9 @@ int drm_gem_vram_pin(struct drm_gem_vram_object *gbo, unsigned long pl_flag) 
	if (gbo->pin_count)

		goto out;



	if (pl_flag)

		drm_gem_vram_placement(gbo, pl_flag);



	for (i = 0; i < gbo->placement.num_placement; ++i)

		gbo->placements[i].flags |= TTM_PL_FLAG_NO_EVICT;
@@ -691,7 +695,15 @@ int drm_gem_vram_driver_gem_prime_pin(struct drm_gem_object *gem) 
{

	struct drm_gem_vram_object *gbo = drm_gem_vram_of_gem(gem);



	return drm_gem_vram_pin(gbo, DRM_GEM_VRAM_PL_FLAG_VRAM);

	/* Fbdev console emulation is the use case of these PRIME

	 * helpers. This may involve updating a hardware buffer from

	 * a shadow FB. We pin the buffer to it's current location

	 * (either video RAM or system memory) to prevent it from

	 * being relocated during the update operation. If you require

	 * the buffer to be pinned to VRAM, implement a callback that

	 * sets the flags accordingly.

	 */

	return drm_gem_vram_pin(gbo, 0);

}

EXPORT_SYMBOL(drm_gem_vram_driver_gem_prime_pin);
@@ -723,7 +735,7 @@ void *drm_gem_vram_driver_gem_prime_vmap(struct drm_gem_object *gem) 
	int ret;

	void *base;



	ret = drm_gem_vram_pin(gbo, DRM_GEM_VRAM_PL_FLAG_VRAM);

	ret = drm_gem_vram_pin(gbo, 0);

	if (ret)

		return NULL;

	base = drm_gem_vram_kmap(gbo, true, NULL);