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[PULL,1/9] mac_via: update comment for VIA1B_vMystery bit

Message ID 20211022071705.471954-2-laurent@vivier.eu
State New
Headers show
Series [PULL,1/9] mac_via: update comment for VIA1B_vMystery bit | expand

Commit Message

Laurent Vivier Oct. 22, 2021, 7:16 a.m. UTC 
From: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>

According to both Linux and NetBSD, port B bit 6 is used on the Quadra 800 to
configure the GLUE logic in A/UX mode. Whilst the name VIA1B_vMystery isn't
particularly descriptive, the patch leaves this to ensure that the constants
in mac_via.c remain in sync with Linux's mac_via.h.

Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
Reviewed-by: Laurent Vivier <laurent@vivier.eu>
Message-Id: <20211020134131.4392-2-mark.cave-ayland@ilande.co.uk>
Signed-off-by: Laurent Vivier <laurent@vivier.eu>
---
 hw/misc/mac_via.c | 4 ++++
 1 file changed, 4 insertions(+)
diff mbox series

Patch

diff --git a/hw/misc/mac_via.c b/hw/misc/mac_via.c
index 993bac017db8..7a53a8b4c04d 100644
--- a/hw/misc/mac_via.c
+++ b/hw/misc/mac_via.c
@@ -130,6 +130,10 @@ 
                                 * On SE/30, vertical sync interrupt enable.
                                 * 0=enabled. This vSync interrupt shows up
                                 * as a slot $E interrupt.
+                                * On Quadra 800 this bit toggles A/UX mode which
+                                * configures the glue logic to deliver some IRQs
+                                * at different levels compared to a classic
+                                * Mac.
                                 */
 #define VIA1B_vADBS2   0x20    /* ADB state input bit 1 (unused on IIfx) */
 #define VIA1B_vADBS1   0x10    /* ADB state input bit 0 (unused on IIfx) */