Re: [Qemu-devel] [PATCH 2/2] Explicitly print out default vnc option in use

[Markus Armbruster <armbru@redhat.com>]

Robert Hu <robert.hu@vmm.sh.intel.com> writes:

> On Wed, 2016-06-08 at 16:22 +0200, Markus Armbruster wrote:
>> Robert Hu <robert.hu@vmm.sh.intel.com> writes:
>> 
>> > On Mon, 2016-06-06 at 09:28 +0200, Markus Armbruster wrote:
>> >> Robert Hu <robert.hu@vmm.sh.intel.com> writes:
>> >> 
>> >> > On Tue, 2016-05-31 at 13:17 +0200, Markus Armbruster wrote:
>> >> >> Robert Hu <robert.hu@vmm.sh.intel.com> writes:
>> >> >> 
>> >> >> > On Tue, 2016-05-31 at 09:51 +0200, Markus Armbruster wrote:
>> > [trim...]
>> >> > I don't see a './configure' option related to this '-vnc to' param. Is
>> >> > there any?
>> >> > '--help', you mean 'qemu-system_x86-64 --help'? or './configure --help'?
>> > [seems repeated contents, trim...]
>> >> > I don't see a './configure' option related to this '-vnc to' param. Is
>> >> > there any?
>> >> > '--help', you mean 'qemu-system_x86-64 --help'? or './configure --help'?
>> >> 
>> >> The former.
>> >> 
>> >> The modern way to select a display is -display.  The older -nographic,
>> >> -curses, -sdl are retained for backward compatibility.
>> >> 
>> >> Relevant parts of -help:
>> >> 
>> >>     Display options:
>> >>     -display sdl[,frame=on|off][,alt_grab=on|off][,ctrl_grab=on|off]
>> >>                 [,window_close=on|off]|curses|none|
>> >>                 gtk[,grab_on_hover=on|off]|
>> >>                 vnc=<display>[,<optargs>]
>> >>                     select display type
>> >>     -nographic      disable graphical output and redirect serial I/Os to console
>> >>     -curses         use a curses/ncurses interface instead of SDL
>> >>     [...]
>> >>     -sdl            enable SDL
>> >>     [...]
>> >>     -vnc display    start a VNC server on display
>> >> 
>> >> Issues:
>> >> 
>> >> * Help for -display is broken: the mutually exclusive option arguments
>> >>   are concatenated.  -display curses and -display none are undocumented.
>> >>   It should look more like this:
>> >> 
>> >>     -display sdl[,frame=on|off][,alt_grab=on|off][,ctrl_grab=on|off]
>> >>                 [,window_close=on|off]|curses|none|
>> >>     -display gtk[,grab_on_hover=on|off]|
>> >>     -display vnc=<display>[,<optargs>]
>> >>     -display curses
>> >>     -display none
>> >>                     select display type
>> >> 
>> >> * -display sdl,gl=on|off and -display gtk,gl=on|off are undocumented
>> >>    (missed in commit 0b71a5d5c and 97edf3b).
>> >> 
>> >> * There is no help on the <display> in -display vnc=<display>.
>> >> 
>> >> * There is no help on the default.  main() picks the default depending
>> >>   on configure options:
>> >> 
>> >>     #if defined(CONFIG_GTK)
>> >>             display_type = DT_GTK;
>> >>     #elif defined(CONFIG_SDL)
>> >>             display_type = DT_SDL;
>> >>     #elif defined(CONFIG_COCOA)
>> >>             display_type = DT_COCOA;
>> >>     #elif defined(CONFIG_VNC)
>> >>             vnc_parse("localhost:0,to=99,id=default", &error_abort);
>> >>             show_vnc_port = 1;
>> >>     #else
>> >>             display_type = DT_NONE;
>> >>     #endif
>> >> 
>> >>   Help should show the default this binary will pick.  This is what I
>> >>   meant by "Ideally, --help output would show the defaults for this
>> >>   build's configuration."
>> >> 
>> >> * Help should explain syntacic sugar:
>> >>   -curses is sugar for -display curses
>> >>   -sdl is sugar for -display sdl
>> >>   -vnc display is sugar for -display vnc=display
>> >> 
>> >>   -nographic is also sugar, but too complicated to explain; I'd leave it
>> >>   as is.
>> >> 
>> >> Non-issue
>> >> 
>> >> * Help shows options even when they're not compiled in.  That's okay,
>> >>   because trying to use them fails with an "FOO support is disabled"
>> >>   error message.
>> >> 
>> >> >> If we decide users need more information than the current "VNC server
>> >> >> running on" line, perhaps it should be included right in that line.
>> >> 
>> >> This would complement, but not replace better -help ouput.
>> >> 
>> >> If you would like to work on these issues, let us know.
>> >
>> > OK, if not in a hurry and assuming this is not a huge amount of work.
>> > I also need to look into the build arch so that completely understand
>> > your 'the default this binary will pick', till now I don't.
>> >
>> > Another concern is that I'm not a native English speaker, so those
>> > description words may not be that apt and concise.
>> 
>> Imperfect English can be addressed in review.  Can be inefficient when
>> most of the work is English rather than code.  But if you want to try
>> anyway, go right ahead regardless.
>
> Hi Markus,
>
> After did some part-time investigation, I'd like to confirm with you:
> this change you required seems also just qemu-options.hx involved, am I
> right?
> If so, I'd like to do that.

Yes, because commmand line option help is defined there.