Re: [Qemu-devel] [PATCH] display: stop using DT_NOGRAPHIC, use DT_NONE

[Michael Tokarev <mjt@tls.msk.ru>]

28.06.2013 15:24, Peter Maydell wrote:
> On 19 June 2013 13:34, Michael Tokarev <mjt@tls.msk.ru> wrote:
>> It looks like initially there was -nographic option to turn
>> off display, now there's another option of the same sort,
>> -display none.  But code in other places of qemu checks for
>> DT_NOGRAPHIC and does not work well with -display none.
>> Make DT_NOGRAPHIC an internal version which selects DT_NONE,
>> and check for that in all other places where previously we
>> checked for DT_NOGRAPHIC.
>>
>> While at it, rename two private variants of display (DT_DEFAULT
>> and DT_NOGRAPHIC) to use two underscores and make them negative,
>> and set DT_NONE to 0.
>>
>> This should fix the issue of non-working sun serial console
>> with the suggested replacement of -nographic which is
>> -display none.
> 
> Note that "-display none" and "-nographic" aren't exactly
> equivalent -- the latter is an option which turns on a bunch
> of behaviour including but not limited to "-display none".

Exactly.  See ab51b1d568e02c80b1abf9016bda3a86dc1db389
for a bit more context of this.

>> I'm not still sure we really want to check for display type
>> in qemu-char.c where we allow/disallow signals delivery from
>> terminal, -- for other display types (CURSES) this makes no
>> good sense.
> 
> ...in particular I don't think "-display none" should
> mean "don't allow ctrl-c" (though -nographic should
> continue to have that effect), and this patch currently
> introduces that behaviour change.

As Anthony said before, -nographic is legacy.  So there should
be some more modern way to control this.  That's exactly the
change which I don't like myself.  But "don't allow ctrl-c"
which is currently bound to -nographic is equally wrong.

>> +    DT__DEFAULT = -1,   /* private */
> I think these could use a slightly longer comment than just "private",
> eg "private, used internally by vl.c only".

Okay.