Re: port-i386/49678: DRM errors with i386 i915drmkms on 82915GM (eeepc 900)

[Taylor R Campbell <riastradh%NetBSD.org@localhost>]

   Date: Thu, 12 Mar 2015 14:42:15 -0400 (EDT)
   From: MLH <mlh%goathill.org@localhost>

   No progress on this up to and including 
   NetBSD 7.99.6 (GENERIC) #7: Tue Mar 10 17:04:14 EDT 2015 GENERIC i386

   The LVDS display goes black when the switch to gfx console occurs.

If you can get xrandr output, you can presumably get dmesg output too.
Can you apply the attached patch, and send me the dmesg output?

Index: sys/arch/x86/x86/bus_space.c
===================================================================
RCS file: /cvsroot/src/sys/arch/x86/x86/bus_space.c,v
retrieving revision 1.38
diff -p -u -r1.38 bus_space.c
--- sys/arch/x86/x86/bus_space.c	27 Jan 2012 18:53:07 -0000	1.38
+++ sys/arch/x86/x86/bus_space.c	18 Mar 2015 13:20:58 -0000
@@ -153,6 +153,8 @@ x86_bus_space_mallocok(void)
 	ioport_malloc_safe = 1;
 }
 
+#include <ddb/ddb.h>
+
 int
 bus_space_map(bus_space_tag_t t, bus_addr_t bpa, bus_size_t size,
 		int flags, bus_space_handle_t *bshp)
@@ -161,6 +163,12 @@ bus_space_map(bus_space_tag_t t, bus_add
 	bus_space_tag_t it;
 	int error;
 
+	if (bpa <= 0xc0000 && 0xc0000 - bpa < size) {
+		printf("%s: mapping vga rom\n", __func__);
+		db_stack_trace_print((db_expr_t)(intptr_t)
+		    __builtin_frame_address(0), true, 65536, "", printf);
+	}
+
 	if ((t->bst_exists & BUS_SPACE_OVERRIDE_MAP) == 0)
 		;	/* skip override */
 	else for (it = t; it != NULL; it = it->bst_super) {