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

[Robert Hu <robert.hu@vmm.sh.intel.com>]

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.

> 
> [...]