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[Qemu-devel] Re: [FOR 0.12 PATCH v3 05/21] default devices: core code &
From: |
Gerd Hoffmann |
Subject: |
[Qemu-devel] Re: [FOR 0.12 PATCH v3 05/21] default devices: core code & serial lines. |
Date: |
Tue, 08 Dec 2009 10:23:40 +0100 |
User-agent: |
Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.4pre) Gecko/20090922 Fedora/3.0-3.9.b4.fc12 Lightning/1.0pre Thunderbird/3.0b4 |
Hi,
Doesn't make sense. The list is not about *creating* default devices, but
about *not* creating them.
Why do we need a negative list? Wouldn't it be a lot more useful to have
positive lists? Maybe I'm just missing the whole point of your patchset though.
Probably the latter ;)
The situation we have right is (with the serial lines as example, the
same applies to some other devices as well):
(1) If you start qemu without any arguments, it will automagically
create a chardev for the serial line (serial_hds[]), which then
will be used by machine->init() to create the (board-specific)
serial lines.
(2) If you start qemu with -serial <something> the specified chardev
will be created and assigned to serial_hds[], which again will be
used by machine->init() ...
Worked fine before qdev appeared. Now we also can create serial lines
like this:
(3) Start qemu with '-device isa-serial,...'.
Problem is this clashes with (1) and qemu will attempt to create the
serial port twice. So this patchset introduces default_serial
(+friends) to fix this issue. The new workflow is:
* default_serial defaults to enabled, when qemu finds it still enabled
after processing all command line the automagic default serial line
is actually created.
* If qemu finds '-serial <something>' it clears default_serial.
* If qemu finds '-device isa-serial,...' it clears default_serial.
- this fixes the conflict mentioned above.
- other serial drivers can be added to the list if needed to solve
the same conflict for them.
* If qemu finds '-nodefaults' it clears default_serial (and the
others).
- new feature, figured this could be useful.
What we could do on top of the above is:
* If the board has the machine->no_serial flag set, clear
default_serial.
s390 could set that flag then and qemu would stop creating a chardev for
a serial line nobody will ever use because s390 has no serial ports.
/me hopes the whole picture is more clear now.
cheers,
Gerd
- [Qemu-devel] [FOR 0.12 PATCH v3 03/21] chardev: move greeting into vc backend., (continued)
- [Qemu-devel] [FOR 0.12 PATCH v3 03/21] chardev: move greeting into vc backend., Gerd Hoffmann, 2009/12/07
- [Qemu-devel] [FOR 0.12 PATCH v3 01/21] Revert "monitor: Command-line flag to enable control mode", Gerd Hoffmann, 2009/12/07
- [Qemu-devel] [FOR 0.12 PATCH v3 05/21] default devices: core code & serial lines., Gerd Hoffmann, 2009/12/07
- [Qemu-devel] Re: [FOR 0.12 PATCH v3 05/21] default devices: core code & serial lines., Alexander Graf, 2009/12/07
- [Qemu-devel] Re: [FOR 0.12 PATCH v3 05/21] default devices: core code & serial lines., Gerd Hoffmann, 2009/12/07
- [Qemu-devel] Re: [FOR 0.12 PATCH v3 05/21] default devices: core code & serial lines., Alexander Graf, 2009/12/07
- [Qemu-devel] Re: [FOR 0.12 PATCH v3 05/21] default devices: core code & serial lines., Gerd Hoffmann, 2009/12/07
- [Qemu-devel] Re: [FOR 0.12 PATCH v3 05/21] default devices: core code & serial lines., Alexander Graf, 2009/12/07
- [Qemu-devel] Re: [FOR 0.12 PATCH v3 05/21] default devices: core code & serial lines., Gerd Hoffmann, 2009/12/07
- [Qemu-devel] Re: [FOR 0.12 PATCH v3 05/21] default devices: core code & serial lines., Alexander Graf, 2009/12/07
- [Qemu-devel] Re: [FOR 0.12 PATCH v3 05/21] default devices: core code & serial lines.,
Gerd Hoffmann <=
[Qemu-devel] Re: [FOR 0.12 PATCH v3 05/21] default devices: core code & serial lines., Alexander Graf, 2009/12/07
[Qemu-devel] [FOR 0.12 PATCH v3 11/21] default devices: network, Gerd Hoffmann, 2009/12/07
[Qemu-devel] [FOR 0.12 PATCH v3 12/21] default devices: drives, Gerd Hoffmann, 2009/12/07
[Qemu-devel] [FOR 0.12 PATCH v3 08/21] zap serial_monitor_mux, Gerd Hoffmann, 2009/12/07
[Qemu-devel] [FOR 0.12 PATCH v3 09/21] default devices: vga adapter., Gerd Hoffmann, 2009/12/07
[Qemu-devel] [FOR 0.12 PATCH v3 07/21] default devices: qemu monitor., Gerd Hoffmann, 2009/12/07
[Qemu-devel] [FOR 0.12 PATCH v3 10/21] default devices: add global cmd line option., Gerd Hoffmann, 2009/12/07