[v3,0/3] Fix regression introduced by disabling accelerated scrolling in fbcon

Message

Helge Deller Feb. 1, 2022, 6:59 p.m. UTC

This series reverts two patches which disabled scrolling acceleration in
fbcon/fbdev. Those patches introduced a regression for fbdev-supported graphic
cards because of the performance penalty by doing screen scrolling by software
instead of using existing 2D hardware acceleration.

The third patch introduces a new config option
CONFIG_FRAMEBUFFER_CONSOLE_LEGACY_ACCELERATION, which -if enabled- switches
fbcon to utilize the bitblt and fillrect hardware acceleration in the
framebuffer console. If disabled, such acceleration will not be used, even if
it is supported by the graphics hardware driver.

This series is being discussed on linux-fbdev and dri-devel mailing lists.

Helge

Helge Deller (3):
  Revert "fbdev: Garbage collect fbdev scrolling acceleration, part 1
    (from TODO list)"
  Revert "fbcon: Disable accelerated scrolling"
  fbcon: Add option to enable legacy hardware acceleration

 Documentation/gpu/todo.rst              |  24 -
 drivers/video/console/Kconfig           |  11 +
 drivers/video/fbdev/core/bitblit.c      |  16 +
 drivers/video/fbdev/core/fbcon.c        | 557 +++++++++++++++++++++++-
 drivers/video/fbdev/core/fbcon.h        |  72 +++
 drivers/video/fbdev/core/fbcon_ccw.c    |  28 +-
 drivers/video/fbdev/core/fbcon_cw.c     |  28 +-
 drivers/video/fbdev/core/fbcon_rotate.h |   9 +
 drivers/video/fbdev/core/fbcon_ud.c     |  37 +-
 drivers/video/fbdev/core/tileblit.c     |  16 +
 drivers/video/fbdev/skeletonfb.c        |  12 +-
 include/linux/fb.h                      |   2 +-
 12 files changed, 744 insertions(+), 68 deletions(-)