From: Gerd Hoffmann <kraxel@redhat.com>
To: "Michael S. Tsirkin" <mst@redhat.com>
Cc: qemu-devel@nongnu.org
Subject: [Qemu-devel] Re: [PATCH] spice: add qxl device
Date: Wed, 17 Nov 2010 14:28:21 +0100 [thread overview]
Message-ID: <4CE3D875.9020701@redhat.com> (raw)
In-Reply-To: <20101116174306.GC4077@redhat.com>
On 11/16/10 18:43, Michael S. Tsirkin wrote:
> On Tue, Nov 02, 2010 at 02:34:58PM +0100, Gerd Hoffmann wrote:
>> + if (ram_size< 32 * 1024 * 1024)
>> + ram_size = 32 * 1024 * 1024;
>> + vga_common_init(vga, ram_size);
>> + vga_init(vga);
>> + register_ioport_write(0x3c0, 16, 1, qxl_vga_ioport_write, vga);
>> + register_ioport_write(0x3b4, 2, 1, qxl_vga_ioport_write, vga);
>> + register_ioport_write(0x3d4, 2, 1, qxl_vga_ioport_write, vga);
>> + register_ioport_write(0x3ba, 1, 1, qxl_vga_ioport_write, vga);
>> + register_ioport_write(0x3da, 1, 1, qxl_vga_ioport_write, vga);
>> +
>> + vga->ds = graphic_console_init(qxl_hw_update, qxl_hw_invalidate,
>> + qxl_hw_screen_dump, qxl_hw_text_update, qxl);
>> + qxl->ssd.ds = vga->ds;
>> + qxl->ssd.bufsize = (16 * 1024 * 1024);
>> + qxl->ssd.buf = qemu_malloc(qxl->ssd.bufsize);
>> +
>> + qxl0 = qxl;
>
> What happens when this device is then removed?
Better don't try ...
The primary vga can't be hot-unplugged in qemu. Not only because the
qxl0 pointer would point into nowhere in this case, but also because you
can't unregister the graphic console. Also having non-pci ressources
(legacy vga I/O ports) is a problem.
>> + pci_config_set_class(config, PCI_CLASS_DISPLAY_VGA);
>> + } else {
>> + pci_config_set_class(config, PCI_CLASS_DISPLAY_OTHER);
>
> So 1st device has device id different from the rest?
Yes.
> Why?
Because the first one actually *is* different. It is the only one which
is vga compatible. It serves as primary display. You'll see the boot
messages there.
>> + device_id++;
>
> what happens when this wraps around?
> Since it's an int probably undefined behaviour ...
I doubt you'll see it wrap in any real world scenario. Even with one
hotplug + unplug cycle per second you'll need a bunch of years to see it
wrap. Beside that at least in windows the device can't be unplugged in
the first place, windows will veto the unplug request.
cheers,
Gerd
next prev parent reply other threads:[~2010-11-17 13:28 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-11-02 13:34 [Qemu-devel] [PATCH] spice: add qxl device Gerd Hoffmann
2010-11-16 14:24 ` Anthony Liguori
2010-11-17 13:14 ` Gerd Hoffmann
2010-11-16 17:43 ` [Qemu-devel] " Michael S. Tsirkin
2010-11-17 13:28 ` Gerd Hoffmann [this message]
2010-11-17 13:58 ` Michael S. Tsirkin
2010-11-17 15:20 ` Gerd Hoffmann
2010-11-17 16:42 ` Michael S. Tsirkin
2010-11-17 17:02 ` Gerd Hoffmann
2010-11-17 18:00 ` Michael S. Tsirkin
2010-11-18 8:09 ` Gleb Natapov
2010-11-18 8:22 ` Gerd Hoffmann
2010-11-18 9:08 ` Michael S. Tsirkin
2010-11-18 10:46 ` Gerd Hoffmann
2010-11-18 9:03 ` Michael S. Tsirkin
2010-11-18 9:11 ` Gleb Natapov
2010-11-18 9:30 ` Michael S. Tsirkin
2010-11-18 9:57 ` Gleb Natapov
2010-11-18 11:33 ` Michael S. Tsirkin
2010-11-18 11:55 ` Gleb Natapov
2010-11-18 12:03 ` Michael S. Tsirkin
2010-11-18 12:27 ` Gleb Natapov
2010-11-18 14:04 ` Michael S. Tsirkin
2010-11-18 14:57 ` Gleb Natapov
2010-11-18 15:25 ` Michael S. Tsirkin
2010-11-18 15:42 ` Gleb Natapov
2010-11-18 16:04 ` Michael S. Tsirkin
2010-11-18 16:10 ` Gleb Natapov
2010-11-18 16:14 ` Michael S. Tsirkin
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