From: David Eger <eger@havoc.gtf.org>
Improve heuristics to favor panning over copyarea() thanks to pseudocode
from Antonino Daplas <adaplas@hotpop.com>
Signed-off-by: David Eger <eger@havoc.gtf.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
---
25-akpm/drivers/video/console/fbcon.c | 36 ++++++++++++++++++----------------
1 files changed, 20 insertions(+), 16 deletions(-)
diff -puN drivers/video/console/fbcon.c~fbcon-prefer-pan-when-available drivers/video/console/fbcon.c
--- 25/drivers/video/console/fbcon.c~fbcon-prefer-pan-when-available 2004-06-03 19:32:56.825296824 -0700
+++ 25-akpm/drivers/video/console/fbcon.c 2004-06-03 19:32:56.830296064 -0700
@@ -1469,22 +1469,26 @@ static void fbcon_bmove_rec(struct vc_da
static __inline__ void updatescrollmode(struct display *p, struct fb_info *info, struct vc_data *vc)
{
int cap = info->flags;
-
- if ((cap & FBINFO_HWACCEL_COPYAREA) && !(cap & FBINFO_HWACCEL_DISABLED))
- p->scrollmode = SCROLL_ACCEL;
- else if ((cap & FBINFO_HWACCEL_YWRAP) &&
- divides(info->fix.ywrapstep, vc->vc_font.height) &&
- divides(vc->vc_font.height, info->var.yres_virtual))
- p->scrollmode = SCROLL_WRAP;
- else if ((cap & FBINFO_HWACCEL_YPAN) &&
- divides(info->fix.ypanstep, vc->vc_font.height) &&
- info->var.yres_virtual >= info->var.yres + vc->vc_font.height)
- p->scrollmode = SCROLL_PAN;
- else if (cap & FBINFO_READS_FAST)
- /* okay, we'll use software version of accel funcs... */
- p->scrollmode = SCROLL_ACCEL;
- else
- p->scrollmode = SCROLL_REDRAW;
+ int good_pan = (cap & FBINFO_HWACCEL_YPAN)
+ && divides(info->fix.ypanstep, vc->vc_font.height)
+ && info->var.yres_virtual >= 2*info->var.yres;
+ int good_wrap = (cap & FBINFO_HWACCEL_YWRAP)
+ && divides(info->fix.ywrapstep, vc->vc_font.height)
+ && divides(vc->vc_font.height, info->var.yres_virtual);
+ int reading_fast = cap & FBINFO_READS_FAST;
+ int fast_copyarea = (cap & FBINFO_HWACCEL_COPYAREA) && !(cap & FBINFO_HWACCEL_DISABLED);
+
+ if (good_wrap || good_pan) {
+ if (reading_fast || fast_copyarea)
+ p->scrollmode = good_wrap ? SCROLL_WRAP : SCROLL_PAN;
+ else
+ p->scrollmode = SCROLL_REDRAW;
+ } else {
+ if (reading_fast || fast_copyarea)
+ p->scrollmode = SCROLL_ACCEL;
+ else
+ p->scrollmode = SCROLL_REDRAW;
+ }
}
static int fbcon_resize(struct vc_data *vc, unsigned int width,
_