video: tegra: dc: prevent nvmap_unpin crash

This is a workaround to make sure serialization of flip worker,
for Android specific.
Android doesn't need mutiple workqueues per each window
since it gets composited one from user layer.
If the last windows' argument index is not 0,
provided change will make the last index to 0 with swap operation
so work will be queued into one workqueue all the time.

Bug 929993
Bug 932592
Bug 933831
Bug 935623
Bug 934569

Change-Id: Ic467bb4f593c72ae98ea1fb324cf1a6d343faa62
Signed-off-by: Min-wuk Lee <mlee@nvidia.com>
Reviewed-on: http://git-master/r/82971
Reviewed-by: Simone Willett <swillett@nvidia.com>
Tested-by: Simone Willett <swillett@nvidia.com>

Rebase-Id: Rc454558f5527de0ec1dc3c93422e182f928c8d41

1 files changed, 21 insertions, 1 deletions

diff --git a/drivers/video/tegra/dc/ext/dev.c b/drivers/video/tegra/dc/ext/dev.c
index 56aa3ced2..63f70485b 100644
--- a/drivers/video/tegra/dc/ext/dev.c
+++ b/drivers/video/tegra/dc/ext/dev.c
@@ -1,7 +1,7 @@
 /*
  * drivers/video/tegra/dc/dev.c
  *
- * Copyright (C) 2011, NVIDIA Corporation
+ * Copyright (C) 2011-2012, NVIDIA Corporation
  *
  * Author: Robert Morell <rmorell@nvidia.com>
  * Some code based on fbdev extensions written by:
@@ -399,6 +399,11 @@ static int tegra_dc_ext_flip(struct tegra_dc_ext_user *user,
         int work_index;
         int i, ret = 0;
 
+#ifdef CONFIG_ANDROID
+        int index_check[DC_N_WINDOWS] = {0, };
+        int zero_index_id = 0;
+#endif
+
         if (!user->nvmap)
                 return -EFAULT;
 
@@ -413,6 +418,21 @@ static int tegra_dc_ext_flip(struct tegra_dc_ext_user *user,
         INIT_WORK(&data->work, tegra_dc_ext_flip_worker);
         data->ext = ext;
 
+#ifdef CONFIG_ANDROID
+        for (i = 0; i < DC_N_WINDOWS; i++) {
+                index_check[i] = args->win[i].index;
+                if (index_check[i] == 0)
+                        zero_index_id = i;
+        }
+
+        if (index_check[DC_N_WINDOWS - 1] != 0) {
+                struct tegra_dc_ext_flip_windowattr win_temp;
+                win_temp = args->win[DC_N_WINDOWS - 1];
+                args->win[DC_N_WINDOWS - 1] = args->win[zero_index_id];
+                args->win[zero_index_id] = win_temp;
+        }
+#endif
+
         for (i = 0; i < DC_N_WINDOWS; i++) {
                 struct tegra_dc_ext_flip_win *flip_win = &data->win[i];
                 int index = args->win[i].index;