svga: Fix banded DMA upload

A previous commit ("winsys/svga: Limit the maximum DMA hardware buffer
size") made banded DMA transfer kick in when transfering gnome-shell
window contents under gnome-shell / wayland. This uncovered a bug where
we assumed that banded DMA transfers always occur to the top (y=0) of the
surface.
Fix this by taking the destination y offset into account.

Cc: 19.2 19.3 20.0 <mesa-stable@lists.freedesktop.org>
Fixes: 287c94ea498 ("Squashed commit of the following:")
Signed-off-by: Thomas Hellstrom <thellstrom@vmware.com>
Reviewed-by: Brian Paul <brianp@vmware.com>
Reviewed-by: Charmaine Lee <charmainel@vmware.com>
Reviewed-by: Roland Scheidegger <sroland@vmware.com>
Tested-by: Marge Bot <https://gitlab.freedesktop.org/mesa/mesa/merge_requests/3733>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/merge_requests/3733>

diff --git a/src/gallium/drivers/svga/svga_resource_texture.c b/src/gallium/drivers/svga/svga_resource_texture.c
index b57d2d7ee95538370090863f11e0a66441e46f50..4cc58e001c0a0eab6b73f85f76ecb442dbc75219 100644 (file)
--- a/src/gallium/drivers/svga/svga_resource_texture.c
+++ b/src/gallium/drivers/svga/svga_resource_texture.c
@@ -133,25 +133,26 @@ svga_transfer_dma(struct svga_context *svga,
       }
    }
    else {
-      int y, h, srcy;
+      int y, h, y_max;
       unsigned blockheight =
          util_format_get_blockheight(st->base.resource->format);
 
       h = st->hw_nblocksy * blockheight;
-      srcy = 0;
+      y_max = st->box.y + st->box.h;
 
-      for (y = 0; y < st->box.h; y += h) {
+      for (y = st->box.y; y < y_max; y += h) {
          unsigned offset, length;
          void *hw, *sw;
 
-         if (y + h > st->box.h)
-            h = st->box.h - y;
+         if (y + h > y_max)
+            h = y_max - y;
 
          /* Transfer band must be aligned to pixel block boundaries */
          assert(y % blockheight == 0);
          assert(h % blockheight == 0);
 
-         offset = y * st->base.stride / blockheight;
+         /* First band starts at the top of the SW buffer. */
+         offset = (y - st->box.y) * st->base.stride / blockheight;
          length = h * st->base.stride / blockheight;
 
          sw = (uint8_t *) st->swbuf + offset;
@@ -159,9 +160,9 @@ svga_transfer_dma(struct svga_context *svga,
          if (transfer == SVGA3D_WRITE_HOST_VRAM) {
             unsigned usage = PIPE_TRANSFER_WRITE;
 
-            /* Wait for the previous DMAs to complete */
-            /* TODO: keep one DMA (at half the size) in the background */
-            if (y) {
+            /* Don't write to an in-flight DMA buffer. Synchronize or
+             * discard in-flight storage. */
+            if (y != st->box.y) {
                svga_context_flush(svga, NULL);
                usage |= PIPE_TRANSFER_DISCARD_WHOLE_RESOURCE;
             }
@@ -177,7 +178,7 @@ svga_transfer_dma(struct svga_context *svga,
          svga_transfer_dma_band(svga, st, transfer,
                                 st->box.x, y, st->box.z,
                                 st->box.w, h, st->box.d,
-                                0, srcy, 0, flags);
+                                0, 0, 0, flags);
 
          /*
           * Prevent the texture contents to be discarded on the next band