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authorAntonino A. Daplas <adaplas@gmail.com>2006-06-26 11:26:29 +0400
committerLinus Torvalds <torvalds@g5.osdl.org>2006-06-26 20:58:29 +0400
commit3007683144b2d53008363f5a7b36a78c53710db4 (patch)
treedc738feee436ec164fb841f82d015f33e9d36e83 /drivers/video/fbmon.c
parent22f4a00fd5207a107fb81984f7b4cc09e5047b45 (diff)
downloadlinux-3007683144b2d53008363f5a7b36a78c53710db4.tar.xz
[PATCH] fbdev: More accurate sync range extrapolation
The EDID block should specify the display's operating limits (vertical and horizontal sync ranges, and maximum dot clock). If not given by the EDID block, the ranges are extrapolated from the modelist. However, the computation used is only a rough approximation, and the resulting values may not reflect the actual capability of the display. This problem is frequently encountered when the EDID block has a single entry, the single mode entry will fail validation. To prevent this, calculate the values based on the same method used in fb_validate_mode(). 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/fbmon.c')
-rw-r--r--drivers/video/fbmon.c28
1 files changed, 24 insertions, 4 deletions
diff --git a/drivers/video/fbmon.c b/drivers/video/fbmon.c
index fbbcb7156a34..87b0224d2347 100644
--- a/drivers/video/fbmon.c
+++ b/drivers/video/fbmon.c
@@ -605,6 +605,7 @@ static int fb_get_monitor_limits(unsigned char *edid, struct fb_monspecs *specs)
block = edid + DETAILED_TIMING_DESCRIPTIONS_START;
DPRINTK(" Monitor Operating Limits: ");
+
for (i = 0; i < 4; i++, block += DETAILED_TIMING_DESCRIPTION_SIZE) {
if (edid_is_limits_block(block)) {
specs->hfmin = H_MIN_RATE * 1000;
@@ -618,11 +619,12 @@ static int fb_get_monitor_limits(unsigned char *edid, struct fb_monspecs *specs)
break;
}
}
-
+
/* estimate monitor limits based on modes supported */
if (retval) {
- struct fb_videomode *modes;
+ struct fb_videomode *modes, *mode;
int num_modes, i, hz, hscan, pixclock;
+ int vtotal, htotal;
modes = fb_create_modedb(edid, &num_modes);
if (!modes) {
@@ -632,20 +634,38 @@ static int fb_get_monitor_limits(unsigned char *edid, struct fb_monspecs *specs)
retval = 0;
for (i = 0; i < num_modes; i++) {
- hz = modes[i].refresh;
+ mode = &modes[i];
pixclock = PICOS2KHZ(modes[i].pixclock) * 1000;
- hscan = (modes[i].yres * 105 * hz + 5000)/100;
+ htotal = mode->xres + mode->right_margin + mode->hsync_len
+ + mode->left_margin;
+ vtotal = mode->yres + mode->lower_margin + mode->vsync_len
+ + mode->upper_margin;
+
+ if (mode->vmode & FB_VMODE_INTERLACED)
+ vtotal /= 2;
+
+ if (mode->vmode & FB_VMODE_DOUBLE)
+ vtotal *= 2;
+
+ hscan = (pixclock + htotal / 2) / htotal;
+ hscan = (hscan + 500) / 1000 * 1000;
+ hz = (hscan + vtotal / 2) / vtotal;
if (specs->dclkmax == 0 || specs->dclkmax < pixclock)
specs->dclkmax = pixclock;
+
if (specs->dclkmin == 0 || specs->dclkmin > pixclock)
specs->dclkmin = pixclock;
+
if (specs->hfmax == 0 || specs->hfmax < hscan)
specs->hfmax = hscan;
+
if (specs->hfmin == 0 || specs->hfmin > hscan)
specs->hfmin = hscan;
+
if (specs->vfmax == 0 || specs->vfmax < hz)
specs->vfmax = hz;
+
if (specs->vfmin == 0 || specs->vfmin > hz)
specs->vfmin = hz;
}