diff options
Diffstat (limited to 'drivers/video/console')
| -rw-r--r-- | drivers/video/console/vgacon.c | 36 |
1 files changed, 34 insertions, 2 deletions
diff --git a/drivers/video/console/vgacon.c b/drivers/video/console/vgacon.c index 8ef1579fa57f..9176fff9ce6e 100644 --- a/drivers/video/console/vgacon.c +++ b/drivers/video/console/vgacon.c @@ -138,8 +138,40 @@ static inline void vga_set_mem_top(struct vc_data *c) static void vgacon_scrolldelta(struct vc_data *c, int lines) { - vc_scrolldelta_helper(c, lines, vga_rolled_over, (void *)vga_vram_base, - vga_vram_size); + unsigned long scr_end = c->vc_scr_end - vga_vram_base; + unsigned long vorigin = c->vc_visible_origin - vga_vram_base; + unsigned long origin = c->vc_origin - vga_vram_base; + int margin = c->vc_size_row * 4; + int from, wrap, from_off, avail; + + /* Turn scrollback off */ + if (!lines) { + c->vc_visible_origin = c->vc_origin; + return; + } + + /* Do we have already enough to allow jumping from 0 to the end? */ + if (vga_rolled_over > scr_end + margin) { + from = scr_end; + wrap = vga_rolled_over + c->vc_size_row; + } else { + from = 0; + wrap = vga_vram_size; + } + + from_off = (vorigin - from + wrap) % wrap + lines * c->vc_size_row; + avail = (origin - from + wrap) % wrap; + + /* Only a little piece would be left? Show all incl. the piece! */ + if (avail < 2 * margin) + margin = 0; + if (from_off < margin) + from_off = 0; + if (from_off > avail - margin) + from_off = avail; + + c->vc_visible_origin = vga_vram_base + (from + from_off) % wrap; + vga_set_mem_top(c); } |