diff options
| -rw-r--r-- | src/display.c | 15 |
1 files changed, 12 insertions, 3 deletions
diff --git a/src/display.c b/src/display.c index e6755e6..db2033e 100644 --- a/src/display.c +++ b/src/display.c @@ -665,9 +665,18 @@ int display_scan_whole_screen(display_t *d, int num_vertical_tiles, int num_hori } } - /* We've just read the full screen; may as well use it */ - destroy_shm_image(d, d->fullscreen); - d->fullscreen = fullscreen_new; + /* Note: it is tempting to replace d->fullscreen now, but that causes + display glitches. The issue is the optimization in scanner_push. + That will cause us to discard a SCANLINE_SCAN_REPORT if there + is a whole screen SCANLINE_DAMAGE_REPORT right behind it. That logic is + reasonable, if the scan will continue to find a problem. But replacing + d->fullscreen now will cause that damage report to fail to find any + problems, and we'll have discarded a valid scan report. + You can modify scan.c to drop that optimization for DAMAGE reports, + but a naive perf analysis suggests that actually costs you. + This is partly because call to display_copy_image_into_fullscreen + in handle_scan_report() still occurs, so you haven't saved that time. */ + destroy_shm_image(d, fullscreen_new); return ret; } |