When attaching on an alpha system, get the current textmode resolution by

querying the 6845 registers, and preserve it if it is larger than 80x25 yet
plausible.

This is necessary to properly operate on the Alphabook 1 where the vga display
is running in a 100x37 textmode.

Other platforms are not affected.

2 files changed, 74 insertions, 4 deletions

diff --git a/sys/dev/ic/vga.c b/sys/dev/ic/vga.c
index bc8639282ed..da71f35e703 100644
--- a/sys/dev/ic/vga.c
+++ b/sys/dev/ic/vga.c
@@ -1,4 +1,4 @@
-/* $OpenBSD: vga.c,v 1.66 2015/07/18 00:48:05 miod Exp $ */
+/* $OpenBSD: vga.c,v 1.67 2015/07/26 03:17:07 miod Exp $ */
 /* $NetBSD: vga.c,v 1.28.2.1 2000/06/30 16:27:47 simonb Exp $ */
 
 /*-
@@ -109,6 +109,7 @@ void	vga_init_screen(struct vga_config *, struct vgascreen *,
     const struct wsscreen_descr *, int, long *);
 void	vga_init(struct vga_config *, bus_space_tag_t, bus_space_tag_t);
 void	vga_setfont(struct vga_config *, struct vgascreen *);
+void	vga_pick_monitor_type(struct vga_config *);
 
 int	vga_mapchar(void *, int, unsigned int *);
 int	vga_putchar(void *, int, int, u_int, long);
@@ -497,10 +498,20 @@ vga_init(struct vga_config *vc, bus_space_tag_t iot, bus_space_tag_t memt)
 				&vh->vh_memh))
                 panic("vga_common_setup: mem subrange failed");
 
+#ifdef __alpha__
+	vga_pick_monitor_type(vc);
+#endif
+
 	vc->nscreens = 0;
 	LIST_INIT(&vc->screens);
 	vc->active = NULL;
-	vc->currenttype = vh->vh_mono ? &vga_stdscreen_mono : &vga_stdscreen;
+#ifdef __alpha__
+	if (vc->custom_list.screens != NULL)
+		vc->currenttype = vc->custom_list.screens[0];
+	else
+#endif
+		vc->currenttype =
+		    vh->vh_mono ? &vga_stdscreen_mono : &vga_stdscreen;
 
 	vc->vc_fonts[0] = &vga_builtinfont;
 	for (i = 1; i < VGA_MAXFONT; i++)
@@ -547,7 +558,14 @@ vga_extended_attach(struct device *self, bus_space_tag_t iot,
 	vc->vc_mmap = map;
 
 	aa.console = console;
-	aa.scrdata = (vc->hdl.vh_mono ? &vga_screenlist_mono : &vga_screenlist);
+#ifdef __alpha__
+	if (vc->custom_list.screens != NULL)
+		aa.scrdata = &vc->custom_list;
+	else
+#endif
+		aa.scrdata =
+		    vc->hdl.vh_mono ? &vga_screenlist_mono : &vga_screenlist;
+
 	aa.accessops = &vga_accessops;
 	aa.accesscookie = vc;
 	aa.defaultscreens = 0;
@@ -1240,6 +1258,51 @@ vga_restore_fonts(struct vga_config *vc)
 	}
 }
 
+#ifdef __alpha__
+void
+vga_pick_monitor_type(struct vga_config *vc)
+{
+	struct vga_handle *vh = &vc->hdl;
+
+	/*
+	 * The Tadpole Alphabook1 uses a 800x600 flat panel in text mode,
+	 * causing the display console to really be 100x37 instead of the
+	 * usual 80x25.
+	 * We attempt to detect this here by checking the CRTC registers.
+	 */
+	unsigned int hend, oflow, vend;
+	unsigned int width, height;
+
+	hend = vga_6845_read(vh, hdisple);
+	oflow = vga_6845_read(vh, overfll);
+	vend = vga_6845_read(vh, vde);
+	if (oflow & 0x02)
+		vend |= 0x100;
+	if (oflow & 0x40)
+		vend |= 0x200;
+
+	width = hend + 1;
+	height = (vend + 1) / 16;
+
+	/* check that the values sound plausible */
+	if ((width > 80 && width <= 128) && (height > 25 && height <= 50)) {
+		snprintf(vc->custom_scr.name, sizeof(vc->custom_scr.name),
+		    "%ux%u", width, height);
+		vc->custom_scr.ncols = width;
+		vc->custom_scr.nrows = height;
+		vc->custom_scr.textops = &vga_emulops;
+		vc->custom_scr.fontwidth = 8;
+		vc->custom_scr.fontheight = 16;
+		vc->custom_scr.capabilities =
+		    WSSCREEN_WSCOLORS | WSSCREEN_HILIT | WSSCREEN_BLINK;
+		vc->custom_scrlist[0] = &vc->custom_scr;
+		vc->custom_list.nscreens = 1;
+		vc->custom_list.screens =
+		    (const struct wsscreen_descr **)vc->custom_scrlist;
+	}
+}
+#endif
+
 struct cfdriver vga_cd = {
 	NULL, "vga", DV_DULL
 };
diff --git a/sys/dev/ic/vgavar.h b/sys/dev/ic/vgavar.h
index 29f5217f690..a3b52ccd486 100644
--- a/sys/dev/ic/vgavar.h
+++ b/sys/dev/ic/vgavar.h
@@ -1,4 +1,4 @@
-/* $OpenBSD: vgavar.h,v 1.12 2015/03/29 18:45:22 miod Exp $ */
+/* $OpenBSD: vgavar.h,v 1.13 2015/07/26 03:17:07 miod Exp $ */
 /* $NetBSD: vgavar.h,v 1.4 2000/06/17 07:11:50 soda Exp $ */
 
 /*
@@ -75,6 +75,13 @@ struct vga_config {
 	paddr_t (*vc_mmap)(void *, off_t, int);
 
 	struct timeout vc_switch_timeout;
+
+#ifdef __alpha__
+	/* placeholder for a custom wsscreen_descr for odd resolutions */
+	struct wsscreen_descr custom_scr;
+	struct wsscreen_descr *custom_scrlist[1];
+	struct wsscreen_list custom_list;
+#endif
 };
 
 static inline u_int8_t _vga_attr_read(struct vga_handle *, int);