diff options
| author | Thomas Zimmermann | 2019-09-23 19:27:42 +0200 |
|---|---|---|
| committer | Thomas Zimmermann | 2019-09-27 09:48:53 +0200 |
| commit | 245f44e77101df44e1074c765732b5613579179d (patch) | |
| tree | 693f95401b38e089642993b9229fb6931b82fc68 /drivers/gpu | |
| parent | 2ebb6701654e0d625eac6c32832d72f8e875c01a (diff) | |
drm/vram: Support top-down placement flag
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>
Diffstat (limited to 'drivers/gpu')
| -rw-r--r-- | drivers/gpu/drm/drm_gem_vram_helper.c | 18 |
1 files changed, 15 insertions, 3 deletions
diff --git a/drivers/gpu/drm/drm_gem_vram_helper.c b/drivers/gpu/drm/drm_gem_vram_helper.c index 49588de88959..dc7942981f4a 100644 --- a/drivers/gpu/drm/drm_gem_vram_helper.c +++ b/drivers/gpu/drm/drm_gem_vram_helper.c @@ -58,6 +58,7 @@ static void drm_gem_vram_placement(struct drm_gem_vram_object *gbo, { unsigned int i; unsigned int c = 0; + u32 invariant_flags = pl_flag & TTM_PL_FLAG_TOPDOWN; gbo->placement.placement = gbo->placements; gbo->placement.busy_placement = gbo->placements; @@ -65,15 +66,18 @@ static void drm_gem_vram_placement(struct drm_gem_vram_object *gbo, if (pl_flag & TTM_PL_FLAG_VRAM) gbo->placements[c++].flags = TTM_PL_FLAG_WC | TTM_PL_FLAG_UNCACHED | - TTM_PL_FLAG_VRAM; + TTM_PL_FLAG_VRAM | + invariant_flags; if (pl_flag & TTM_PL_FLAG_SYSTEM) gbo->placements[c++].flags = TTM_PL_MASK_CACHING | - TTM_PL_FLAG_SYSTEM; + TTM_PL_FLAG_SYSTEM | + invariant_flags; if (!c) gbo->placements[c++].flags = TTM_PL_MASK_CACHING | - TTM_PL_FLAG_SYSTEM; + TTM_PL_FLAG_SYSTEM | + invariant_flags; gbo->placement.num_placement = c; gbo->placement.num_busy_placement = c; @@ -238,6 +242,14 @@ out: * the buffer is pinned at its current location (video RAM or system * memory). * + * Small buffer objects, such as cursor images, can lead to memory + * fragmentation if they are pinned in the middle of video RAM. This + * is especially a problem on devices with only a small amount of + * video RAM. Fragmentation can prevent the primary framebuffer from + * fitting in, even though there's enough memory overall. The modifier + * DRM_GEM_VRAM_PL_FLAG_TOPDOWN marks the buffer object to be pinned + * at the high end of the memory region to avoid fragmentation. + * * Returns: * 0 on success, or * a negative error code otherwise. |