exo: Set the gfx::NativePixmapHandle modifier

This will forward the modifier all the way to the eventual EGLImage or
gbm bo import such that GLES or KMS will properly understand the
buffer layout.

BUG=b:145579089, b:79682290
TEST=wayland_rects_client --use-drm=msm and verify modifiers get passed

Change-Id: Ia422c3713f1a9384aa737c3d1cccb1dd76709e18
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2314984
Commit-Queue: Kristian H. Kristensen <hoegsberg@chromium.org>
Reviewed-by: Daniele Castagna <dcastagna@chromium.org>
Reviewed-by: Fritz Koenig <frkoenig@chromium.org>
Cr-Commit-Position: refs/heads/master@{#793405}

components/exo/wayland/zwp_linux_dmabuf.cc

@@ -51,6 +51,7 @@ struct LinuxBufferParams {
     base::ScopedFD fd;
     uint32_t stride;
     uint32_t offset;
+    uint64_t modifier;
   };
 
   explicit LinuxBufferParams(Display* display) : display(display) {}
@@ -74,7 +75,8 @@ void linux_buffer_params_add(wl_client* client,
   LinuxBufferParams* linux_buffer_params =
       GetUserDataAs<LinuxBufferParams>(resource);
 
-  LinuxBufferParams::Plane plane{base::ScopedFD(fd), stride, offset};
+  const uint64_t modifier = (static_cast<uint64_t>(modifier_hi) << 32) | modifier_lo;
+  LinuxBufferParams::Plane plane{base::ScopedFD(fd), stride, offset, modifier};
 
   const auto& inserted = linux_buffer_params->planes.insert(
       std::pair<uint32_t, LinuxBufferParams::Plane>(plane_idx,
@@ -106,8 +108,16 @@ bool ValidateLinuxBufferParams(wl_resource* resource,
 
   LinuxBufferParams* linux_buffer_params =
       GetUserDataAs<LinuxBufferParams>(resource);
-  size_t num_planes = gfx::NumberOfPlanesForLinearBufferFormat(format);
 
+  size_t num_planes = linux_buffer_params->planes.size();
+  if (num_planes == 0) {
+    wl_resource_post_error(resource,
+                          ZWP_LINUX_BUFFER_PARAMS_V1_ERROR_INCOMPLETE,
+                          "no planes given");
+    return false;
+  }
+
+  // Validate that we have planes 0..num_planes-1
   for (uint32_t i = 0; i < num_planes; ++i) {
     auto plane_it = linux_buffer_params->planes.find(i);
     if (plane_it == linux_buffer_params->planes.end()) {
@@ -118,7 +128,24 @@ bool ValidateLinuxBufferParams(wl_resource* resource,
     }
   }
 
-  if (linux_buffer_params->planes.size() != num_planes) {
+  // All planes must have the same modifier.
+  uint64_t modifier = linux_buffer_params->planes[0].modifier;
+  for (uint32_t i = 0; i < num_planes; ++i) {
+    if (linux_buffer_params->planes[i].modifier != modifier) {
+      wl_resource_post_error(resource,
+                             ZWP_LINUX_BUFFER_PARAMS_V1_ERROR_INVALID_FORMAT,
+                             "all planes must have same modifier");
+      return false;
+    }
+  }
+
+  // For linear layouts we know how many planes to expect, so check
+  // that.  Otherwise, we have to trust that the client gave us the
+  // right number and fail later when importing the EGLImage if that's
+  // wrong.
+  if (modifier == DRM_FORMAT_MOD_LINEAR &&
+      linux_buffer_params->planes.size() !=
+          gfx::NumberOfPlanesForLinearBufferFormat(format)) {
     wl_resource_post_error(resource, ZWP_LINUX_BUFFER_PARAMS_V1_ERROR_PLANE_IDX,
                            "plane idx out of bounds");
     return false;
@@ -153,14 +180,12 @@ wl_resource* create_buffer(wl_client* client,
   LinuxBufferParams* linux_buffer_params =
       GetUserDataAs<LinuxBufferParams>(resource);
 
-  size_t num_planes =
-      gfx::NumberOfPlanesForLinearBufferFormat(supported_format->buffer_format);
-
   gfx::NativePixmapHandle handle;
 
-  for (uint32_t i = 0; i < num_planes; ++i) {
-    auto plane_it = linux_buffer_params->planes.find(i);
-    LinuxBufferParams::Plane& plane = plane_it->second;
+  handle.modifier = linux_buffer_params->planes[0].modifier;
+
+  for (uint32_t i = 0; i < linux_buffer_params->planes.size(); ++i) {
+    auto& plane = linux_buffer_params->planes[i];
     handle.planes.emplace_back(plane.stride, plane.offset, 0,
                                std::move(plane.fd));
   }