From a6c3464f69cf5a8a31eb31cc436e7dbd325b8ff9 Mon Sep 17 00:00:00 2001 From: Thomas Zimmermann Date: Thu, 13 Jun 2019 09:30:33 +0200 Subject: [PATCH] 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: Thomas Zimmermann Acked-by: Gerd Hoffmann Link: https://patchwork.freedesktop.org/patch/msgid/20190613073041.29350-2-tzimmermann@suse.de --- drivers/gpu/drm/drm_gem_vram_helper.c | 20 ++++++++++++++++---- 1 file changed, 16 insertions(+), 4 deletions(-) diff --git a/drivers/gpu/drm/drm_gem_vram_helper.c b/drivers/gpu/drm/drm_gem_vram_helper.c index 42ad80888df7..f3e5803affb0 100644 --- a/drivers/gpu/drm/drm_gem_vram_helper.c +++ b/drivers/gpu/drm/drm_gem_vram_helper.c @@ -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; - drm_gem_vram_placement(gbo, pl_flag); + 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); -- 2.45.2