Re: [PATCH 3/5] drm/i915: Add a function to mmap framebuffer obj

[Das, Nirmoy]

Hi Andi,

On 4/4/2023 6:57 PM, Andi Shyti wrote:

Hi Nirmoy,

[...]

+int i915_gem_fb_mmap(struct drm_i915_gem_object *obj, struct vm_area_struct 
*vma)
+{
+       struct drm_i915_private *i915 = to_i915(obj->base.dev);
+       struct drm_device *dev = &i915->drm;
+       struct i915_mmap_offset *mmo = NULL;
+       enum i915_mmap_type mmap_type;
+       struct i915_ggtt *ggtt = to_gt(i915)->ggtt;
+
+       if (drm_dev_is_unplugged(dev))
+               return -ENODEV;
+
+       /* handle ttm object */
+       if (obj->ops->mmap_ops) {
+               /*
+                * ttm fault handler, ttm_bo_vm_fault_reserved() uses fake 
offset
+                * to calculate page offset so set that up.
+                */
+               vma->vm_pgoff += drm_vma_node_start(&obj->base.vma_node);

you could have kept my r-b.

I wasn't sure, so I removed it :)

  Good work here!

Reviewed-by: Andi Shyti <andi.sh...@linux.intel.com>

Thanks,

Nirmoy

Thanks,
Andi

+       } else {
+               /* handle stolen and smem objects */
+               mmap_type = i915_ggtt_has_aperture(ggtt) ? I915_MMAP_TYPE_GTT : 
I915_MMAP_TYPE_WC;
+               mmo = mmap_offset_attach(obj, mmap_type, NULL);
+               if (!mmo)
+                       return -ENODEV;
+       }
+
+       /*
+        * When we install vm_ops for mmap we are too late for
+        * the vm_ops->open() which increases the ref_count of
+        * this obj and then it gets decreased by the vm_ops->close().
+        * To balance this increase the obj ref_count here.
+        */
+       obj = i915_gem_object_get(obj);
+       return i915_gem_object_mmap(obj, mmo, vma);
+}