From 1276cc97d1e6437c7fbc43fdd5cbcea39f60acee Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Alex=20Villac=C3=ADs=20Lasso?= <a_villacis@palosanto.com>
Date: Fri, 27 Jul 2018 16:08:52 +0000
Subject: [PATCH] renderer/native: Fallback to non-planar API if
 gbm_bo_get_handle_for_plane fails

Commit c0d9b08ef9bf2be865aad9bf1bc74ba24c655d9f replaced the old GBM API calls
with the multi-plane GBM API. However, the call to gbm_bo_get_handle_for_plane
fails for some DRI drivers (in particular i915). Due to missing error checks,
the subsequent call to drmModeAddFB[2] fails and the screen output locks up.

This commit adds the missing error checks and falls back to the old GBM API
(non-planar) if necessary.

v5: test success of gbm_bo_get_handle_for_plane instead of errno

This commit adopts solution proposed by Daniel van Vugt to check the return
value of gbm_bo_get_handle_for_plane on plane 0 and fall back to old
non-planar method if the call fails. This removes the errno check (for
ENOSYS) that could abort if mesa ever sets a different value.

Related to: https://gitlab.gnome.org/GNOME/mutter/issues/127


(cherry picked from commit f7af32a3eaefabbea3ebbda3a93eff98dd105ab9)
---
 src/backends/native/meta-renderer-native.c | 21 ++++++++++++++++-----
 1 file changed, 16 insertions(+), 5 deletions(-)

diff --git a/src/backends/native/meta-renderer-native.c b/src/backends/native/meta-renderer-native.c
index fc6b22302..59003b397 100644
--- a/src/backends/native/meta-renderer-native.c
+++ b/src/backends/native/meta-renderer-native.c
@@ -1607,12 +1607,23 @@ gbm_get_next_fb_id (MetaGpuKms         *gpu_kms,
       return FALSE;
     }
 
-  for (i = 0; i < gbm_bo_get_plane_count (next_bo); i++)
+  if (gbm_bo_get_handle_for_plane (next_bo, 0).s32 == -1)
     {
-      strides[i] = gbm_bo_get_stride_for_plane (next_bo, i);
-      handles[i] = gbm_bo_get_handle_for_plane (next_bo, i).u32;
-      offsets[i] = gbm_bo_get_offset (next_bo, i);
-      modifiers[i] = gbm_bo_get_modifier (next_bo);
+      /* Failed to fetch handle to plane, falling back to old method */
+      strides[0] = gbm_bo_get_stride (next_bo);
+      handles[0] = gbm_bo_get_handle (next_bo).u32;
+      offsets[0] = 0;
+      modifiers[0] = DRM_FORMAT_MOD_INVALID;
+    }
+  else
+    {
+      for (i = 0; i < gbm_bo_get_plane_count (next_bo); i++)
+        {
+          strides[i] = gbm_bo_get_stride_for_plane (next_bo, i);
+          handles[i] = gbm_bo_get_handle_for_plane (next_bo, i).u32;
+          offsets[i] = gbm_bo_get_offset (next_bo, i);
+          modifiers[i] = gbm_bo_get_modifier (next_bo);
+        }
     }
 
   kms_fd = meta_gpu_kms_get_fd (gpu_kms);
-- 
2.19.0