[src/trunk]: src/sys/arch/mac68k/obio From Ken'ichi Ishizaka: correct the ca...

[scottr <scottr%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/8062b395b438
branches:  trunk
changeset: 472357:8062b395b438
user:      scottr <scottr%NetBSD.org@localhost>
date:      Wed Apr 28 05:24:08 1999 +0000

description:
>From Ken'ichi Ishizaka:  correct the calculation of the frame buffer
offset by masking off garbage bits in the DAFB v7.  This has been
tested at all resolutions and common color depths on the LC47x.

diffstat:

 sys/arch/mac68k/obio/grf_obio.c |  17 ++++++++++-------
 1 files changed, 10 insertions(+), 7 deletions(-)

diffs (41 lines):

diff -r beb675914866 -r 8062b395b438 sys/arch/mac68k/obio/grf_obio.c
--- a/sys/arch/mac68k/obio/grf_obio.c   Wed Apr 28 05:10:38 1999 +0000
+++ b/sys/arch/mac68k/obio/grf_obio.c   Wed Apr 28 05:24:08 1999 +0000
@@ -1,4 +1,4 @@
-/*     $NetBSD: grf_obio.c,v 1.41 1999/01/06 07:08:19 scottr Exp $     */
+/*     $NetBSD: grf_obio.c,v 1.42 1999/04/28 05:24:08 scottr Exp $     */
 
 /*
  * Copyright (C) 1998 Scott Reynolds
@@ -238,22 +238,25 @@
 
                /* Compute the current frame buffer offset */
                vbase1 = bus_space_read_4(sc->sc_tag, sc->sc_regh, 0x0) & 0xfff;
-               vbase2 = bus_space_read_4(sc->sc_tag, sc->sc_regh, 0x4) & 0xf;
-               sc->sc_fbofs = (vbase1 << 9) | (vbase2 << 5);
-
 #if 1
                /*
-                * XXX The following hack exists because the DAFB v7 in these
-                * systems doesn't compute fbofs correctly. (sar 19980813)
+                * XXX The following exists because the DAFB v7 in these
+                * systems doesn't return reasonable values to use for fbofs.
+                * Ken'ichi Ishizaka gets credit for this hack.  (sar 19990426)
+                * (Does this get us the correct result for _all_ DAFB-
+                * equipped systems and monitor combinations?  It seems
+                * possible, if not likely...)
                 */
                switch (current_mac_model->machineid) {
                case MACH_MACLC475:
                case MACH_MACLC475_33:
                case MACH_MACLC575:
-                       sc->sc_fbofs = 0x1000;
+                       vbase1 &= 0x3f;
                        break;
                }
 #endif
+               vbase2 = bus_space_read_4(sc->sc_tag, sc->sc_regh, 0x4) & 0xf;
+               sc->sc_fbofs = (vbase1 << 9) | (vbase2 << 5);
 
                printf(" @ %lx: DAFB video subsystem, monitor sense %x\n",
                    sc->sc_basepa + sc->sc_fbofs,