tridentfb: y-panning fixes
The Trident cards uses only 20-bit address of screen start in double
words. This allows addressing for only 4MB of video memory so check this.
Also remove some redundant checks and assignments.
Signed-off-by: Krzysztof Helt <krzysztof.h1@wp.pl>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
diff --git a/drivers/video/tridentfb.c b/drivers/video/tridentfb.c
index 1c3f0ba..138140b 100644
--- a/drivers/video/tridentfb.c
+++ b/drivers/video/tridentfb.c
@@ -870,8 +870,10 @@
line_length = var->xres_virtual * bpp / 8;
}
- if (var->yres > var->yres_virtual)
- var->yres_virtual = var->yres;
+ /* datasheet specifies how to set panning only up to 4 MB */
+ if (line_length * (var->yres_virtual - var->yres) > (4 << 20))
+ var->yres_virtual = ((4 << 20) / line_length) + var->yres;
+
if (line_length * var->yres_virtual > info->fix.smem_len)
return -EINVAL;
@@ -944,8 +946,6 @@
debug("enter\n");
offset = (var->xoffset + (var->yoffset * var->xres_virtual))
* var->bits_per_pixel / 32;
- info->var.xoffset = var->xoffset;
- info->var.yoffset = var->yoffset;
set_screen_start(par, offset);
debug("exit\n");
return 0;
@@ -1225,7 +1225,6 @@
((blue & 0xFF00) >> 8);
}
-/* debug("exit\n"); */
return 0;
}