Add another check to com probe

With this bentley@'s Steam Deck no longer attaches these:
com0 at isa0 port 0x3f8/8 irq 4: ns8250, no fifo
com1 at isa0 port 0x2f8/8 irq 3: ns8250, no fifo
com2 at isa0 port 0x3e8/8 irq 5: ns8250, no fifo

From Matthias Drochner in NetBSD rev 1.154
ok kettenis@

diff --git a/sys/dev/ic/com.c b/sys/dev/ic/com.c
index a5ecfde..79717a7 100644 (file)
--- a/sys/dev/ic/com.c
+++ b/sys/dev/ic/com.c
@@ -1,4 +1,4 @@
-/*     $OpenBSD: com.c,v 1.175 2022/01/11 11:51:14 uaa Exp $   */
+/*     $OpenBSD: com.c,v 1.176 2023/04/18 09:58:06 jsg Exp $   */
 /*     $NetBSD: com.c,v 1.82.4.1 1996/06/02 09:08:00 mrg Exp $ */
 
 /*
@@ -146,14 +146,14 @@ comspeed(long freq, long speed)
 int
 comprobe1(bus_space_tag_t iot, bus_space_handle_t ioh)
 {
-       int i, k;
+       int i;
 
        /* force access to id reg */
-       bus_space_write_1(iot, ioh, com_lcr, 0);
+       bus_space_write_1(iot, ioh, com_lcr, LCR_8BITS);
        bus_space_write_1(iot, ioh, com_iir, 0);
        for (i = 0; i < 32; i++) {
-               k = bus_space_read_1(iot, ioh, com_iir);
-               if (k & 0x38) {
+               if ((bus_space_read_1(iot, ioh, com_lcr) != LCR_8BITS) ||
+                   (bus_space_read_1(iot, ioh, com_iir) & 0x38)) {
                        bus_space_read_1(iot, ioh, com_data); /* cleanup */
                } else
                        break;