tridentfb: improved register values on TGUI 9680

Improved values for some registers after Xorg Trident driver.  The main
problem was that values set by BIOS have been ignored.

This patch completely remove random pixels ("snow") on the TGUI 9680 and
9440 (not supported yet by the driver).  It does not help with the "snow"
on 3DImage and Blade3D cards.

There is also small improvement in timing calculations (hblank start and
vblank start)

Signed-off-by: Krzysztof Helt <krzysztof.h1@wp.pl>
Cc: "Antonino A. Daplas" <adaplas@pol.net>
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 e79788a..9668be8 100644
--- a/drivers/video/tridentfb.c
+++ b/drivers/video/tridentfb.c
@@ -87,7 +87,17 @@
 
 static int is_oldclock(int id)
 {
-	return (id == TGUI9660);
+	return	(id == TGUI9660) ||
+		(id == CYBER9320);
+}
+
+static int is_oldprotect(int id)
+{
+	return	(id == TGUI9660) ||
+		(id == PROVIDIA9685) ||
+		(id == CYBER9320) ||
+		(id == CYBER9382) ||
+		(id == CYBER9385);
 }
 
 static int is_blade(int id)
@@ -143,6 +153,7 @@
 
 	case CYBER9320:
 	case TGUI9660:
+	case PROVIDIA9685:
 	case IMAGE975:
 	case IMAGE985:
 	case BLADE3D:
@@ -905,14 +916,14 @@
 	hsyncend = (var->xres + var->right_margin + var->hsync_len) / 8 - 1;
 	htotal = (var->xres + var->left_margin + var->right_margin +
 		  var->hsync_len) / 8 - 5;
-	hblankstart = hdispend + 2;
+	hblankstart = hdispend + 1;
 	hblankend = htotal + 3;
 
 	vdispend = var->yres - 1;
 	vsyncstart = var->yres + var->lower_margin;
 	vsyncend = vsyncstart + var->vsync_len;
 	vtotal = var->upper_margin + vsyncend - 2;
-	vblankstart = vdispend + 2;
+	vblankstart = vdispend + 1;
 	vblankend = vtotal;
 
 	crtc_unlock(par);
@@ -1020,15 +1031,18 @@
 
 	write3X4(par, PixelBusReg, tmp);
 
-	tmp = 0x10;
+	tmp = read3X4(par, DRAMControl);
+	if (!is_oldprotect(par->chip_id))
+		tmp |= 0x10;
 	if (iscyber(par->chip_id))
 		tmp |= 0x20;
 	write3X4(par, DRAMControl, tmp);	/* both IO, linear enable */
 
 	write3X4(par, InterfaceSel, read3X4(par, InterfaceSel) | 0x40);
-	write3X4(par, Performance, 0x92);
+	if (!is_xp(par->chip_id))
+		write3X4(par, Performance, read3X4(par, Performance) | 0x10);
 	/* MMIO & PCI read and write burst enable */
-	write3X4(par, PCIReg, 0x07);
+	write3X4(par, PCIReg, read3X4(par, PCIReg) | 0x06);
 
 	/* convert from picoseconds to kHz */
 	vclk = PICOS2KHZ(info->var.pixclock);
@@ -1230,6 +1244,9 @@
 		revision = vga_io_rseq(RevisionID);
 
 		switch (revision) {
+		case 0x21:
+			chip_id = PROVIDIA9685;
+			break;
 		case 0x22:
 		case 0x23:
 			chip_id = CYBER9397;