Re: Sun4D SMP now works OK, serial console broken - was Re: More

["David S. Miller" <davem@davemloft.net>]

On Thu, 9 Sep 2004 10:19:35 -0700
William Lee Irwin III <wli@holomorphy.com> wrote:

> On Thu, 9 Sep 2004, C.Newport wrote:
> >> My SS1000E seems to be stable with 2.4.27 after fitting a frame
> >> buffer and keyboard. It rebuilds a kernel OK in SMP mode.
> >> Serial console is still broken, there seems to be a problem
> >> with the sunzilog driver.
> >> What other Sun machines use sunzilog.c as the serial console ?.
> >> Is this problem really a sun4d issue or is it generic to sunzilog ?
> 
> On Thu, Sep 09, 2004 at 12:55:19PM -0400, Chris Ricker wrote:
> > I think early Ultras (Ultra2, for example) are Sun Zilog as well. I've not 
> > tried serial console on mine in a while though....
> 
> Yes, SunZilog appears to be stable on all my UltraSPARC machines. The
> bug is likely something specific to older revisions typically used in
> sun4d boxen or some such.

Like the UltraSPARC Enterprise bigger systems using the
SunZILOG's for serial, the XBUS/XDBUS on sun4d can
defer the completion of writes to I/O registers.

Thus you should play around with enabling the
__sparc_v9__ version of the ZS_WSYNC() macro
in drivers/sbus/char/zs.c for all Sparc builds.

Something like this:

=== drivers/sbus/char/zs.c 1.11 vs edited ==--- 1.11/drivers/sbus/char/zs.c	2002-03-30 07:45:50 -08:00
+++ edited/drivers/sbus/char/zs.c	2004-09-09 10:20:18 -07:00
@@ -71,13 +71,13 @@
 #ifndef __sparc_v9__
 #define ZSDELAY()		udelay(5)
 #define ZSDELAY_LONG()		udelay(20)
-#define ZS_WSYNC(channel)	do { } while(0)
 #else
 #define ZSDELAY()
 #define ZSDELAY_LONG()
+#endif
+
 #define ZS_WSYNC(__channel) \
 	sbus_readb(&((__channel)->control))
-#endif
 
 struct sun_zslayout **zs_chips;
 struct sun_zschannel **zs_channels;