Re: [PATCH 54/67] ui/vc: console-vc requires PIXMAN

[Marc-André Lureau]

Hi

On Fri, Sep 1, 2023 at 9:28 PM Daniel P. Berrangé <berrange@redhat.com> wrote:
>
> On Wed, Aug 30, 2023 at 01:38:28PM +0400, marcandre.lureau@redhat.com wrote:
> > From: Marc-André Lureau <marcandre.lureau@redhat.com>
> >
> > Add stubs for the fallback paths.
> >
> > Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
> > ---
> >  ui/console-vc-stubs.c | 59 +++++++++++++++++++++++++++++++++++++++++++
> >  ui/meson.build        |  2 +-
> >  2 files changed, 60 insertions(+), 1 deletion(-)
> >  create mode 100644 ui/console-vc-stubs.c
> >
> > diff --git a/ui/console-vc-stubs.c b/ui/console-vc-stubs.c
> > new file mode 100644
> > index 0000000000..76ea880d27
> > --- /dev/null
> > +++ b/ui/console-vc-stubs.c
> > @@ -0,0 +1,59 @@
> > +/*
> > + * SPDX-License-Identifier: GPL-2.0-or-later
> > + * QEMU VC stubs
> > + */
> > +#include "qemu/osdep.h"
> > +
> > +#include "qapi/error.h"
> > +#include "qemu/error-report.h"
> > +#include "qemu/option.h"
> > +#include "chardev/char.h"
> > +#include "ui/console-priv.h"
> > +
> > +void qemu_text_console_select(QemuTextConsole *c)
> > +{
> > +}
> > +
> > +const char * qemu_text_console_get_label(QemuTextConsole *c)
> > +{
> > +    return NULL;
> > +}
> > +
> > +void qemu_text_console_update_cursor(void)
> > +{
> > +}
> > +
> > +void qemu_text_console_handle_keysym(QemuTextConsole *s, int keysym)
> > +{
> > +}
> > +
> > +#define TYPE_CHARDEV_VC "chardev-vc"
> > +
> > +static void vc_chr_parse(QemuOpts *opts, ChardevBackend *backend, Error 
> > **errp)
> > +{
> > +    const char *id = qemu_opts_id(opts);
> > +
> > +    warn_report("%s: this is a dummy VC driver. "
> > +                "Use '-nographic' or a different chardev.", id);
> > +}
>
> Why should this be an error_setg() call given we have a errp
> parameter, so make this unsupportable config into an error ?
> Ignoring invalid user configs is not desirable in general.

This was to keep starting as default, regardless of pixman support.

Since, by default, QEMU will create the following VCs (vl.c):

            add_device_config(DEV_SERIAL, "vc:80Cx24C");
            add_device_config(DEV_PARALLEL, "vc:80Cx24C");
            monitor_parse("vc:80Cx24C", "readline", false);

With SDL or VNC, this will associate the QemuTextConsole(s), which is
disabled without pixman. Maybe we shouldn't create those VC by default
when the backend doesn't support it (but to null instead).

Yes, if the user supplied -chardev vc manually, we should error out
instead. I'll try to update the patch.



(btw, I agree with you it would have been nice to make VC an abstract
base chardev, and only allow final types)

>
> > +
> > +static void char_vc_class_init(ObjectClass *oc, void *data)
> > +{
> > +    ChardevClass *cc = CHARDEV_CLASS(oc);
> > +
> > +    cc->parse = vc_chr_parse;
> > +}
> > +
> > +static const TypeInfo char_vc_type_info = {
> > +    .name = TYPE_CHARDEV_VC,
> > +    .parent = TYPE_CHARDEV,
> > +    .class_init = char_vc_class_init,
> > +};
> > +
> > +void qemu_console_early_init(void)
> > +{
> > +    /* set the default vc driver */
> > +    if (!object_class_by_name(TYPE_CHARDEV_VC)) {
> > +        type_register(&char_vc_type_info);
> > +    }
> > +}
> > diff --git a/ui/meson.build b/ui/meson.build
> > index 0a1e8272a3..3085e10a72 100644
> > --- a/ui/meson.build
> > +++ b/ui/meson.build
> > @@ -6,7 +6,6 @@ system_ss.add(png)
> >  system_ss.add(files(
> >    'clipboard.c',
> >    'console.c',
> > -  'console-vc.c',
> >    'cursor.c',
> >    'input-keymap.c',
> >    'input-legacy.c',
> > @@ -19,6 +18,7 @@ system_ss.add(files(
> >    'ui-qmp-cmds.c',
> >    'util.c',
> >  ))
> > +system_ss.add(when: pixman, if_true: files('console-vc.c'), if_false: 
> > files('console-vc-stubs.c'))
> >  if dbus_display
> >    system_ss.add(files('dbus-module.c'))
> >  endif
> > --
> > 2.41.0
> >
> >
>
> With regards,
> Daniel
> --
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>
>


-- 
Marc-André Lureau