tridentfb: fix clock settings for older Trident 96XX chips

The Xorg code shows that Trident models 9660, 9680 and 9682 require a
different clock setting method.  Add the second clock setting method for older
models.

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 f3153a82f926cee081026d6d93cc3eef1096a984..8ee4261abf3b604d9f4e9ff982e3458b5ce850f0 100644 (file)
--- a/drivers/video/tridentfb.c
+++ b/drivers/video/tridentfb.c
@@ -85,6 +85,11 @@ MODULE_PARM_DESC(fp, "Define if flatpanel is connected");
 module_param(crt, int, 0);
 MODULE_PARM_DESC(crt, "Define if CRT is connected");
 
+static int is_oldclock(int id)
+{
+       return (id == TGUI9660);
+}
+
 static int is_blade(int id)
 {
        return  (id == BLADE3D) ||
@@ -659,23 +664,33 @@ static void set_screen_start(struct tridentfb_par *par, int base)
 static void set_vclk(struct tridentfb_par *par, unsigned long freq)
 {
        int m, n, k;
-       unsigned long f, fi, d, di;
-       unsigned char lo = 0, hi = 0;
+       unsigned long fi, d, di;
+       unsigned char best_m = 0, best_n = 0, best_k = 0;
+       unsigned char hi, lo;
 
        d = 20000;
-       for (k = 2; k >= 0; k--)
-               for (m = 0; m < 63; m++)
-                       for (n = 0; n < 128; n++) {
+       for (k = 1; k >= 0; k--)
+               for (m = 0; m < 32; m++)
+                       for (n = 0; n < 122; n++) {
                                fi = ((14318l * (n + 8)) / (m + 2)) >> k;
                                if ((di = abs(fi - freq)) < d) {
                                        d = di;
-                                       f = fi;
-                                       lo = n;
-                                       hi = (k << 6) | m;
+                                       best_n = n;
+                                       best_m = m;
+                                       best_k = k;
                                }
                                if (fi > freq)
                                        break;
                        }
+
+       if (is_oldclock(par->chip_id)) {
+               lo = best_n | (best_m << 7);
+               hi = (best_m >> 1) | (best_k << 4);
+       } else {
+               lo = best_n;
+               hi = best_m | (best_k << 6);
+       }
+
        if (is3Dchip(par->chip_id)) {
                vga_mm_wseq(par->io_virt, ClockHigh, hi);
                vga_mm_wseq(par->io_virt, ClockLow, lo);