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Re: [Qemu-devel] [PATCH 0/4] vga: new display devices
From: |
Laszlo Ersek |
Subject: |
Re: [Qemu-devel] [PATCH 0/4] vga: new display devices |
Date: |
Thu, 13 Mar 2014 09:41:36 +0100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.3.0 |
On 03/13/14 09:22, Gerd Hoffmann wrote:
>> +---------->IS_PCI_VGA (Pci):
>> | "Found PCI VGA device"
>
>>> + k->class_id = PCI_CLASS_DISPLAY_OTHER;
>>
>> and from qemu's "include/hw/pci/pci_ids.h":
>>
>>> #define PCI_CLASS_DISPLAY_VGA 0x0300
>>> #define PCI_CLASS_DISPLAY_OTHER 0x0380
>>
>> I think this is the cause of the mismatch.
>
> Yes, it is. First byte (0x03) of the class says what it is, second byte
> of class (0x00 / 0x80) specifies the programming interface.
>
> So, it is a display adapter, but it isn't vga compatible, therefore
> specifying PCI_CLASS_DISPLAY_VGA would be asking for trouble as trying
> to program it using the standard vga io ports isn't going to work ...
>
> [ same picture with virtio-gpu btw: The variant with the vga compat
> bits declares itself as PCI_CLASS_DISPLAY_VGA whereas the variant
> without is PCI_CLASS_DISPLAY_OTHER ]
>
>> Does the following OVMF patch help?
>>
>>> - if (IS_PCI_VGA (Pci)) {
>>> + if (IS_PCI_DISPLAY (Pci)) {
>
> Yes.
Please ping me when the series is merged and I will submit the patch
(possibly also correcting the related "Vga" references throughout the file).
Thanks
Laszlo
[Qemu-devel] [PATCH 4/4] virtio-vga: v1, Gerd Hoffmann, 2014/03/12
Re: [Qemu-devel] [PATCH 0/4] vga: new display devices, Laszlo Ersek, 2014/03/12