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>
This commit is contained in:
Krzysztof Helt 2008-07-23 21:31:07 -07:00 committed by Linus Torvalds
parent a4af1798d7
commit f330c4b196

View file

@ -870,8 +870,10 @@ static int tridentfb_check_var(struct fb_var_screeninfo *var,
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 @@ static int tridentfb_pan_display(struct fb_var_screeninfo *var,
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 @@ static int tridentfb_setcolreg(unsigned regno, unsigned red, unsigned green,
((blue & 0xFF00) >> 8);
}
/* debug("exit\n"); */
return 0;
}