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

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Message-Id: <20220815180441.754835347@linuxfoundation.org>
Date:   Mon, 15 Aug 2022 19:50:13 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Daniel Vetter <daniel.vetter@...ll.ch>,
        Helge Deller <deller@....de>
Subject: [PATCH 5.19 0057/1157] fbcon: Fix accelerated fbdev scrolling while logo is still shown

From: Helge Deller <deller@....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@...r.kernel.org # v5.10+
Acked-by: Daniel Vetter <daniel.vetter@...ll.ch>
Signed-off-by: Helge Deller <deller@....de>
Link: https://patchwork.freedesktop.org/patch/msgid/YpkYxk7wsBPx3po+@p100
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.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,