On Tue, Jul 11, 2017 at 3:38 PM, Rob Clark [off-list ref] wrote:

+static unsigned long hijack_firmware_fb(struct drm_device *dev)
+{
+       struct msm_drm_private *priv = dev->dev_private;
+       unsigned long size;
+       int i;
+
+       /* if we have simplefb/efifb, find it's aperture and hijack
+        * that before we kick out the firmware fb's.
+        *
+        * TODO we probably should hold registration_lock
+        */
+       for (i = 0; i < FB_MAX; i++) {
+               struct fb_info *fb = get_fb_info(i);
+
+               if (IS_ERR_OR_NULL(fb))
+                       continue;
+
+               if (!fb->apertures->count)
+                       continue;
+
+               /* if we find efifb or simplefb, we are about to
+                * kick them out, so hijack their memory:
+                */
+               if ((strcmp(fb->fix.id, "EFI VGA") = 0) ||
+                               (strcmp(fb->fix.id, "simple") = 0)) {
+
+                       priv->vram.paddr = fb->apertures->ranges[0].base;
+                       size = fb->apertures->ranges[0].size;
+               }
+
+               put_fb_info(fb);
+
+               if (size)
+                       return size;
+       }
+
+       return 0;
+}

I think this should be a helper function in at least drm_fb_helper.c,
which would then fill in both base&size in a passed-in struct. But
yeah this seems a lot better than the old one.

In the future we could then also extend this with kicking out other
firmware fb things.
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch