diff options
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/gpu/drm/i915/i915_drv.c | 7 | ||||
| -rw-r--r-- | drivers/gpu/drm/i915/i915_drv.h | 1 | ||||
| -rw-r--r-- | drivers/gpu/drm/i915/i915_gem.c | 53 |
3 files changed, 61 insertions, 0 deletions
diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c index 1d2230f7b749..47fe07283d88 100644 --- a/drivers/gpu/drm/i915/i915_drv.c +++ b/drivers/gpu/drm/i915/i915_drv.c @@ -355,6 +355,13 @@ static int i915_getparam(struct drm_device *dev, void *data, case I915_PARAM_MIN_EU_IN_POOL: value = INTEL_INFO(dev)->min_eu_in_pool; break; + case I915_PARAM_MMAP_GTT_VERSION: + /* Though we've started our numbering from 1, and so class all + * earlier versions as 0, in effect their value is undefined as + * the ioctl will report EINVAL for the unknown param! + */ + value = i915_gem_mmap_gtt_version(); + break; default: DRM_DEBUG("Unknown parameter %d\n", param->param); return -EINVAL; diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h index 04b4fd6c32e4..9fdaf23336df 100644 --- a/drivers/gpu/drm/i915/i915_drv.h +++ b/drivers/gpu/drm/i915/i915_drv.h @@ -3218,6 +3218,7 @@ int i915_gem_dumb_create(struct drm_file *file_priv, struct drm_mode_create_dumb *args); int i915_gem_mmap_gtt(struct drm_file *file_priv, struct drm_device *dev, uint32_t handle, uint64_t *offset); +int i915_gem_mmap_gtt_version(void); void i915_gem_track_fb(struct drm_i915_gem_object *old, struct drm_i915_gem_object *new, diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c index 04607d4115d6..d37b44126942 100644 --- a/drivers/gpu/drm/i915/i915_gem.c +++ b/drivers/gpu/drm/i915/i915_gem.c @@ -1680,6 +1680,56 @@ static unsigned int tile_row_pages(struct drm_i915_gem_object *obj) } /** + * i915_gem_mmap_gtt_version - report the current feature set for GTT mmaps + * + * A history of the GTT mmap interface: + * + * 0 - Everything had to fit into the GTT. Both parties of a memcpy had to + * aligned and suitable for fencing, and still fit into the available + * mappable space left by the pinned display objects. A classic problem + * we called the page-fault-of-doom where we would ping-pong between + * two objects that could not fit inside the GTT and so the memcpy + * would page one object in at the expense of the other between every + * single byte. + * + * 1 - Objects can be any size, and have any compatible fencing (X Y, or none + * as set via i915_gem_set_tiling() [DRM_I915_GEM_SET_TILING]). If the + * object is too large for the available space (or simply too large + * for the mappable aperture!), a view is created instead and faulted + * into userspace. (This view is aligned and sized appropriately for + * fenced access.) + * + * Restrictions: + * + * * snoopable objects cannot be accessed via the GTT. It can cause machine + * hangs on some architectures, corruption on others. An attempt to service + * a GTT page fault from a snoopable object will generate a SIGBUS. + * + * * the object must be able to fit into RAM (physical memory, though no + * limited to the mappable aperture). + * + * + * Caveats: + * + * * a new GTT page fault will synchronize rendering from the GPU and flush + * all data to system memory. Subsequent access will not be synchronized. + * + * * all mappings are revoked on runtime device suspend. + * + * * there are only 8, 16 or 32 fence registers to share between all users + * (older machines require fence register for display and blitter access + * as well). Contention of the fence registers will cause the previous users + * to be unmapped and any new access will generate new page faults. + * + * * running out of memory while servicing a fault may generate a SIGBUS, + * rather than the expected SIGSEGV. + */ +int i915_gem_mmap_gtt_version(void) +{ + return 1; +} + +/** * i915_gem_fault - fault a page into the GTT * @area: CPU VMA in question * @vmf: fault info @@ -1694,6 +1744,9 @@ static unsigned int tile_row_pages(struct drm_i915_gem_object *obj) * from the GTT and/or fence registers to make room. So performance may * suffer if the GTT working set is large or there are few fence registers * left. + * + * The current feature set supported by i915_gem_fault() and thus GTT mmaps + * is exposed via I915_PARAM_MMAP_GTT_VERSION (see i915_gem_mmap_gtt_version). */ int i915_gem_fault(struct vm_area_struct *area, struct vm_fault *vmf) { |