[PATCH for-8.2] Revert "ui/console: allow to override the default VC"

[Peter Maydell]

This reverts commit 1bec1cc0da497e55c16e2a7b50f94cdb2a02197f.  This
commit changed the behaviour of the "-display none" option, so that
it now creates a QEMU monitor on the terminal.  "-display none"
should not be tangled up with whether we create a monitor or a serial
terminal; it should purely and only disable the graphical window.
Changing its behaviour like this breaks command lines which, for
example, use semihosting for their output and don't want a graphical
window, as they now get a monitor they never asked for.

It also breaks the command line we document for Xen in
docs/system/i386/xen.html:

 $ ./qemu-system-x86_64 --accel kvm,xen-version=0x40011,kernel-irqchip=split \
    -display none -chardev stdio,mux=on,id=char0,signal=off -mon char0 \
    -device xen-console,chardev=char0  -drive file=${GUEST_IMAGE},if=xen

qemu-system-x86_64: cannot use stdio by multiple character devices
qemu-system-x86_64: could not connect serial device to character backend 'stdio'

Revert the commit to restore the previous handling of "-display
none".

Resolves: https://gitlab.com/qemu-project/qemu/-/issues/1974
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---
 include/ui/console.h |  2 --
 system/vl.c          | 27 ++++++++++-----------------
 ui/console.c         | 17 -----------------
 3 files changed, 10 insertions(+), 36 deletions(-)

diff --git a/include/ui/console.h b/include/ui/console.h
index a4a49ffc640..acb61a7f152 100644
--- a/include/ui/console.h
+++ b/include/ui/console.h
@@ -462,14 +462,12 @@ struct QemuDisplay {
     DisplayType type;
     void (*early_init)(DisplayOptions *opts);
     void (*init)(DisplayState *ds, DisplayOptions *opts);
-    const char *vc;
 };
 
 void qemu_display_register(QemuDisplay *ui);
 bool qemu_display_find_default(DisplayOptions *opts);
 void qemu_display_early_init(DisplayOptions *opts);
 void qemu_display_init(DisplayState *ds, DisplayOptions *opts);
-const char *qemu_display_get_vc(DisplayOptions *opts);
 void qemu_display_help(void);
 
 /* vnc.c */
diff --git a/system/vl.c b/system/vl.c
index 5af7ced2a16..3d64a90f253 100644
--- a/system/vl.c
+++ b/system/vl.c
@@ -1372,7 +1372,6 @@ static void qemu_setup_display(void)
 static void qemu_create_default_devices(void)
 {
     MachineClass *machine_class = MACHINE_GET_CLASS(current_machine);
-    const char *vc = qemu_display_get_vc(&dpy);
 
     if (is_daemonized()) {
         /* According to documentation and historically, -nographic redirects
@@ -1391,30 +1390,24 @@ static void qemu_create_default_devices(void)
         }
     }
 
-    if (nographic || (!vc && !is_daemonized() && isatty(STDOUT_FILENO))) {
-        if (default_parallel) {
+    if (nographic) {
+        if (default_parallel)
             add_device_config(DEV_PARALLEL, "null");
-        }
         if (default_serial && default_monitor) {
             add_device_config(DEV_SERIAL, "mon:stdio");
         } else {
-            if (default_serial) {
+            if (default_serial)
                 add_device_config(DEV_SERIAL, "stdio");
-            }
-            if (default_monitor) {
+            if (default_monitor)
                 monitor_parse("stdio", "readline", false);
-            }
         }
     } else {
-        if (default_serial) {
-            add_device_config(DEV_SERIAL, vc ?: "null");
-        }
-        if (default_parallel) {
-            add_device_config(DEV_PARALLEL, vc ?: "null");
-        }
-        if (default_monitor && vc) {
-            monitor_parse(vc, "readline", false);
-        }
+        if (default_serial)
+            add_device_config(DEV_SERIAL, "vc:80Cx24C");
+        if (default_parallel)
+            add_device_config(DEV_PARALLEL, "vc:80Cx24C");
+        if (default_monitor)
+            monitor_parse("vc:80Cx24C", "readline", false);
     }
 
     if (default_net) {
diff --git a/ui/console.c b/ui/console.c
index 8e688d35695..676d0cbaba2 100644
--- a/ui/console.c
+++ b/ui/console.c
@@ -1677,23 +1677,6 @@ void qemu_display_init(DisplayState *ds, DisplayOptions 
*opts)
     dpys[opts->type]->init(ds, opts);
 }
 
-const char *qemu_display_get_vc(DisplayOptions *opts)
-{
-    assert(opts->type < DISPLAY_TYPE__MAX);
-    if (opts->type == DISPLAY_TYPE_NONE) {
-        return NULL;
-    }
-    assert(dpys[opts->type] != NULL);
-    if (dpys[opts->type]->vc) {
-        return dpys[opts->type]->vc;
-    } else {
-#ifdef CONFIG_PIXMAN
-        return "vc:80Cx24C";
-#endif
-    }
-    return NULL;
-}
-
 void qemu_display_help(void)
 {
     int idx;
-- 
2.34.1