[PATCH 5.19 0057/1157] fbcon: Fix accelerated fbdev scrolling while logo is still shown

Greg Kroah-Hartman
2022-08-15T22:05:21Z

From: Helge Deller <deller@gmx.de>

commit 3866cba87dcd0162fb41e9b3b653d0af68fad5ec upstream.

There is no need to directly skip over to the SCROLL_REDRAW case while
the logo is still shown.

When using DRM, this change has no effect because the code will reach
the SCROLL_REDRAW case immediately anyway.

But if you run an accelerated fbdev driver and have
FRAMEBUFFER_CONSOLE_LEGACY_ACCELERATION enabled, console scrolling is
slowed down by factors so that it feels as if you use a 9600 baud
terminal.

So, drop those unnecessary checks and speed up fbdev console
acceleration during bootup.

Cc: stable@vger.kernel.org # v5.10+
Acked-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Helge Deller <deller@gmx.de>
Link: https://patchwork.freedesktop.org/patch/msgid/YpkYxk7wsBPx3po+@p100
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
drivers/video/fbdev/core/fbcon.c | 4 ----
1 file changed, 4 deletions(-)

--- a/drivers/video/fbdev/core/fbcon.c
+++ b/drivers/video/fbdev/core/fbcon.c
@@ -1760,8 +1760,6 @@ static bool fbcon_scroll(struct vc_data
case SM_UP:
if (count > vc->vc_rows) /* Maximum realistic size */
count = vc->vc_rows;
- if (logo_shown >= 0)
- goto redraw_up;
switch (fb_scrollmode(p)) {
case SCROLL_MOVE:
fbcon_redraw_blit(vc, info, p, t, b - t - count,
@@ -1850,8 +1848,6 @@ static bool fbcon_scroll(struct vc_data
case SM_DOWN:
if (count > vc->vc_rows) /* Maximum realistic size */
count = vc->vc_rows;
- if (logo_shown >= 0)
- goto redraw_down;
switch (fb_scrollmode(p)) {
case SCROLL_MOVE:
fbcon_redraw_blit(vc, info, p, b - 1, b - t - count,