On 09/02/16 00:20, Kristian Høgsberg wrote:
On Fri, Feb 5, 2016 at 5:48 PM, Ben Widawsky <benjamin.widawsky@xxxxxxxxx> wrote:This behavior of checking for a shmem backed GEM object was introduced here: commit 4c914c0c7c787b8f730128a8cdcca9c50b0784ab Author: Brad Volkin <bradley.d.volkin@xxxxxxxxx> Date: Tue Feb 18 10:15:45 2014 -0800 drm/i915: Refactor shmem pread setup It is possible for an object to not be a shmem backed GEM object (for example userptr objects). An example of how we hit this failure can be found through copy_batch() in the command parser because we allocate a userptr object for the batch which contains privileged instructions. Userptr calls drm_gem_private_object_init() which explicitly sets the filp to none. It is equally feasible to simply remove the check altogether. You'll probably oops with get_pages somewhere, but that's okay IMO because this condition should be a driver bug, and not trigger-able by userspace. On this note, the function name could probably benefit from a change, but whatever. NOTE: I manually retyped this from a test machine. So I haven't even compiled this exact patch. Cc: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx> Cc: Kristian Høgsberg <krh@xxxxxxxxxxxxx> Cc: Jordan Justen <jordan.l.justen@xxxxxxxxx> Signed-off-by: Ben Widawsky <benjamin.widawsky@xxxxxxxxx> --- drivers/gpu/drm/i915/i915_gem.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c index 66b1705..a198928 100644 --- a/drivers/gpu/drm/i915/i915_gem.c +++ b/drivers/gpu/drm/i915/i915_gem.c @@ -489,7 +489,7 @@ int i915_gem_obj_prepare_shmem_read(struct drm_i915_gem_object *obj, *needs_clflush = 0; - if (!obj->base.filp) + if (!obj->ops->get_pages)
Don't all subclasses have a get_pages() function?
Do we want to do what Chris did in a2a4f916c2f344d4e596c875dd1e66764afec8b8 (on drm-intel-fixes): + if (WARN_ON((obj->ops->flags & I915_GEM_OBJECT_HAS_STRUCT_PAGE) == 0)) ?
Yes, I think so; i915_gem_shmem_pread() is going to walk the sglist, so the object had better have a page array for it to iterate over.
.Dave. _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
