Autoconfigure the illumosfb driver on illumos framebuffer consoles.

When the kernel console is gfxp_bitmap (VIS identifier "illumos_fb", e.g. a
UEFI GOP framebuffer), list illumosfb after any driver matched for the
primary PCI device and do not list vesa. vesa needs a video BIOS, which UEFI
systems do not have, and a vesa PCI claim together with illumosfb's
framebuffer claim makes xf86PostProbe() abort. A specific PCI driver that
claims the device still wins, because illumosfb then cannot claim the
framebuffer slot.

Not suitable for upstream as is: it depends on OpenIndiana's Solaris autoconfig
changes and the out-of-tree illumosfb driver.

--- a/hw/xfree86/common/xf86AutoConfig.c
+++ b/hw/xfree86/common/xf86AutoConfig.c
@@ -238,7 +238,35 @@
         xf86Msg(X_ERROR, "Error parsing the built-in default configuration.\n");
 
     return ret == CONFIG_OK;
+}
+
+#if defined(__sun) && (defined(__i386__) || defined(__amd64__))
+/*
+ * On illumos a linear framebuffer console (UEFI GOP, or a VESA mode set by
+ * the loader) is provided by gfxp_bitmap, which identifies itself as
+ * "illumos_fb". The illumosfb driver can drive it; vesa cannot without a
+ * video BIOS, and its PCI claim would conflict with illumosfb's framebuffer
+ * claim.
+ */
+static Bool
+sunBitmapConsole(void)
+{
+    struct vis_identifier visid;
+    int fd, iret = -1;
+
+    if (xf86Info.consoleFd >= 0)
+        SYSCALL(iret = ioctl(xf86Info.consoleFd, VIS_GETIDENTIFIER, &visid));
+    if (iret < 0 && (fd = open(xf86SolarisFbDev, O_RDONLY)) >= 0) {
+        SYSCALL(iret = ioctl(fd, VIS_GETIDENTIFIER, &visid));
+        close(fd);
+    }
+    if (iret < 0)
+        return FALSE;
+
+    xf86Msg(X_PROBED, "console driver: %s\n", visid.name);
+    return strcmp(visid.name, "illumos_fb") == 0;
 }
+#endif
 
 static void
 listPossibleVideoDrivers(char *matches[], int nmatches)
@@ -263,6 +291,30 @@
     matches[i++] = xnfstrdup("modesetting");
 #endif
 
+#if defined(__sun) && (defined(__i386__) || defined(__amd64__))
+    /*
+     * Try any specific PCI driver first; if it claims the device, illumosfb
+     * cannot claim the framebuffer slot and stays unused. Otherwise
+     * illumosfb replaces vesa.
+     */
+    if (sunBitmapConsole()) {
+        int j, k;
+
+        for (j = k = 0; j < i; j++) {
+            if (strcmp(matches[j], "vesa") == 0)
+                free(matches[j]);
+            else
+                matches[k++] = matches[j];
+        }
+        for (j = k; j < i; j++)
+            matches[j] = NULL;
+        i = k;
+        if (i < (nmatches - 1))
+            matches[i++] = xnfstrdup("illumosfb");
+        return;
+    }
+#endif
+
 #if !defined(__sun)
     /* Fallback to platform default frame buffer driver */
     if (i < (nmatches - 1)) {