diff options
| -rw-r--r-- | drivers/gpu/drm/i915/gem/i915_gem_domain.c | 6 | ||||
| -rw-r--r-- | include/uapi/drm/i915_drm.h | 29 |
2 files changed, 35 insertions, 0 deletions
diff --git a/drivers/gpu/drm/i915/gem/i915_gem_domain.c b/drivers/gpu/drm/i915/gem/i915_gem_domain.c index 7d1400b13429..43004bef55cb 100644 --- a/drivers/gpu/drm/i915/gem/i915_gem_domain.c +++ b/drivers/gpu/drm/i915/gem/i915_gem_domain.c @@ -268,6 +268,9 @@ int i915_gem_get_caching_ioctl(struct drm_device *dev, void *data, struct drm_i915_gem_object *obj; int err = 0; + if (IS_DGFX(to_i915(dev))) + return -ENODEV; + rcu_read_lock(); obj = i915_gem_object_lookup_rcu(file, args->handle); if (!obj) { @@ -303,6 +306,9 @@ int i915_gem_set_caching_ioctl(struct drm_device *dev, void *data, enum i915_cache_level level; int ret = 0; + if (IS_DGFX(i915)) + return -ENODEV; + switch (args->caching) { case I915_CACHING_NONE: level = I915_CACHE_NONE; diff --git a/include/uapi/drm/i915_drm.h b/include/uapi/drm/i915_drm.h index e54f9efaead0..868c2ee7be60 100644 --- a/include/uapi/drm/i915_drm.h +++ b/include/uapi/drm/i915_drm.h @@ -1395,6 +1395,35 @@ struct drm_i915_gem_busy { * ppGTT support, or if the object is used for scanout). Note that this might * require unbinding the object from the GTT first, if its current caching value * doesn't match. + * + * Note that this all changes on discrete platforms, starting from DG1, the + * set/get caching is no longer supported, and is now rejected. Instead the CPU + * caching attributes(WB vs WC) will become an immutable creation time property + * for the object, along with the GTT caching level. For now we don't expose any + * new uAPI for this, instead on DG1 this is all implicit, although this largely + * shouldn't matter since DG1 is coherent by default(without any way of + * controlling it). + * + * Implicit caching rules, starting from DG1: + * + * - If any of the object placements (see &drm_i915_gem_create_ext_memory_regions) + * contain I915_MEMORY_CLASS_DEVICE then the object will be allocated and + * mapped as write-combined only. + * + * - Everything else is always allocated and mapped as write-back, with the + * guarantee that everything is also coherent with the GPU. + * + * Note that this is likely to change in the future again, where we might need + * more flexibility on future devices, so making this all explicit as part of a + * new &drm_i915_gem_create_ext extension is probable. + * + * Side note: Part of the reason for this is that changing the at-allocation-time CPU + * caching attributes for the pages might be required(and is expensive) if we + * need to then CPU map the pages later with different caching attributes. This + * inconsistent caching behaviour, while supported on x86, is not universally + * supported on other architectures. So for simplicity we opt for setting + * everything at creation time, whilst also making it immutable, on discrete + * platforms. */ struct drm_i915_gem_caching { /** |