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Re: [Qemu-devel] [PATCH 12/16] vga: Convert to isa_register_portio_list.
From: |
Richard Henderson |
Subject: |
Re: [Qemu-devel] [PATCH 12/16] vga: Convert to isa_register_portio_list. |
Date: |
Sun, 18 Sep 2011 07:16:28 -0700 |
User-agent: |
Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.2.22) Gecko/20110906 Fedora/3.1.14-1.fc14 Thunderbird/3.1.14 |
On 09/18/2011 06:45 AM, Avi Kivity wrote:
>> + /* The PCI-ISA bridge should have been configured properly such that
>> + this works for PCI devices as well. This only supports one bridge,
>> + but "secondary" VGA cards are generally accessed by MMIO only
>> anyway. */
>> + isa_register_portio_list(NULL, 0x3b0, vga_portio_list, s, "vga");
>>
>> memory_region_init_io(vga_mem,&vga_mem_ops, s,
>
> This is called even for pci machines which have no ISA bus (and even
> if they did, the code should work wit the pci bus, not ISA). The code
> should return the portio list of the caller to register, or perhaps
> accept a callback to do the registration.
You're over-thinking this. It's all legacy ISA crap full stop.
If the machine doesn't have a PCI-ISA bridge, then the machine will
also be prepared to access the VGA registers via its BARs.
In such a case we just should skip this entire section. Probably
isa_register_portio_list should simply notice no ISA bus has been
registered and do nothing.
r~