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authorAntonino A. Daplas <adaplas@gmail.com>2005-09-09 13:09:58 -0700
committerLinus Torvalds <torvalds@g5.osdl.org>2005-09-09 14:03:39 -0700
commit96fe6a2109db29cd15b90a093c16e6cb4b19371a (patch)
treebd3c424f3f43e6b5a2ba6c235c7c25b3ba197f4c /drivers/video/fbmem.c
parent5251bffc9b4ca699993c79166adf02faf1bbc043 (diff)
[PATCH] fbdev: Add VESA Coordinated Video Timings (CVT) support
The Coordinated Video Timings (CVT) is the latest standard approved by VESA concerning video timings generation. It addresses the limitation of GTF which is designed mainly for CRT displays. CRT's have a high blanking requirement (as much as 25% of the horizontal frame length) which artificially increases the pixelclock. Digital displays, on the other hand, needs to conserve the pixelclock as much as possible. The GTF also does not take into account the different aspect ratios in its calculation. The new function added is fb_find_mode_cvt(). It is called by fb_find_mode() if it recognizes a mode option string formatted for CVT. The format is: <xres>x<yres>[M][R][-<bpp>][<at-sign><refresh>][i][m] The 'M' tells the function to calculate using CVT. On it's own, it will compute a timing for CRT displays at 60Hz. If the 'R' is specified, 'reduced blanking' computation will be used, best for flatpanels. The 'i' and the 'm' is for 'interlaced mode' and 'with margins' respectively. To determine if CVT was used, check for dmesg for something like this: CVT Mode - <pix>M<n>[-R], ie: .480M3-R (800x600 reduced blanking) where: pix - product of xres and yres, in MB M - is a CVT mode n - the aspect ratio (3 - 4:3; 4 - 5:4; 9 - 16:9, 15:9; A - 16:10) -R - reduced blanking Signed-off-by: Antonino Daplas <adaplas@pol.net> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'drivers/video/fbmem.c')
-rw-r--r--drivers/video/fbmem.c12
1 files changed, 4 insertions, 8 deletions
diff --git a/drivers/video/fbmem.c b/drivers/video/fbmem.c
index a815f5e2fcb..71b55070bdb 100644
--- a/drivers/video/fbmem.c
+++ b/drivers/video/fbmem.c
@@ -1029,6 +1029,7 @@ register_framebuffer(struct fb_info *fb_info)
{
int i;
struct fb_event event;
+ struct fb_videomode mode;
if (num_registered_fb == FB_MAX)
return -ENXIO;
@@ -1059,16 +1060,11 @@ register_framebuffer(struct fb_info *fb_info)
}
fb_info->pixmap.offset = 0;
- if (!fb_info->modelist.prev ||
- !fb_info->modelist.next ||
- list_empty(&fb_info->modelist)) {
- struct fb_videomode mode;
-
+ if (!fb_info->modelist.prev || !fb_info->modelist.next)
INIT_LIST_HEAD(&fb_info->modelist);
- fb_var_to_videomode(&mode, &fb_info->var);
- fb_add_videomode(&mode, &fb_info->modelist);
- }
+ fb_var_to_videomode(&mode, &fb_info->var);
+ fb_add_videomode(&mode, &fb_info->modelist);
registered_fb[i] = fb_info;
devfs_mk_cdev(MKDEV(FB_MAJOR, i),