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

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

10.07.2013 01:24, Anthony Liguori wrote:
> Peter Maydell <peter.maydell@linaro.org> writes:
> 
>> On 9 July 2013 21:45, Anthony Liguori <aliguori@us.ibm.com> wrote:
>>> Michael Tokarev <mjt@tls.msk.ru> writes:
>>>> 09.07.2013 22:37, Anthony Liguori wrote:
>>>>> ERROR:/home/aliguori/git/qemu/tests/fw_cfg-test.c:63:test_fw_cfg_nographic: assertion failed (qfw_cfg_get_u16(fw_cfg, FW_CFG_NOGRAPHIC) == 0): (1 == 0)
>>>>> GTester: last random seed: R02S25031265f05e4d41efcf758c9ef6043b
>>>>
>>>> Sure, because the test is bogus.
>>>
>>> No, it's a guest ABI.  You cannot change the guest ABI.
>>
>> Why the heck are we telling the guest that the user
>> specified -nographic anyhow? It's a dumb guest ABI...
> 
> I believe OpenBIOS uses this to determine if it should display messages
> on serial or on the graphic display.

This is actually exactly the thing this very patch changes: it stops
relying on -nographics and passes -display none to the bios/firmware
instead.  And the documentation has been updated accordingly, also in
this very patch:

hw/nvram/fw_cfg.c
-    fw_cfg_add_i16(s, FW_CFG_NOGRAPHIC, (uint16_t)(display_type == DT_NOGRAPHIC));
+    fw_cfg_add_i16(s, FW_CFG_NOGRAPHIC, (uint16_t)(display_type == DT_NONE));

hw/sparc/sun4m.c
     slavio_serial_ms_kbd_init(hwdef->ms_kb_base, slavio_irq[14],
-                              display_type == DT_NOGRAPHIC, ESCC_CLOCK, 1);
+                              display_type == DT_NONE, ESCC_CLOCK, 1);

qemu-options.hx

 @item none
 Do not display video output. The guest will still see an emulated
 graphics card, but its output will not be displayed to the QEMU
-user. This option differs from the -nographic option in that it
+user.  The fact that we have no display is passed to firmware and
+affects a few other places depending on the target architecture,
+like switching console output to serial console or disabling keyboard
+input.
+
+This option differs from the -nographic option in that it
 only affects what is done with video output; -nographic also changes
 the destination of the serial and parallel port data.


Besides, -- I just noticed -- we're discussing a V1 of this patch,
while I already sent a v3, -- it has a much more appropriate logic
for the Ctrl+C handling.  The only issue I see with it is the make
check breakage which is easy to fix by s/==0/==1/.

Thanks,

/mjt