Re: [virtio-dev] [PATCH] Add virtio gpu specification.

[Stefan Hajnoczi <stefanha@redhat.com>]

On Mon, Sep 22, 2014 at 04:25:46PM +0200, Gerd Hoffmann wrote:
> +\begin{description}
> +\item[\field{events_read}] signals pending events to the driver.  The
> +  driver MUST NOT write to this field.
> +\item[\field{events_clear}] clears pending events in the device.
> +  Writing a '1' into a bit will clear the corresponding bit in
> +  \field{events_read}, mimicking write-to-clear behavior.
> +\item[\field{num_scanouts}] specifies the number of scanouts supported
> +  by the device

Please clarify whether this means "the maximum number of scanouts that
this device is able to support" or "the current number of scanouts
available"?

> +\begin{lstlisting}
> +#define VIRTIO_GPU_MAX_SCANOUTS 16
> +struct virtio_gpu_resp_display_info {
> +        struct virtio_gpu_ctrl_hdr hdr;
> +        struct virtio_gpu_display_one {
> +                uint32_t enabled;
> +                uint32_t width;
> +                uint32_t height;
> +                uint32_t x;
> +                uint32_t y;
> +                uint32_t flags;
> +        } pmodes[VIRTIO_GPU_MAX_SCANOUTS];

Why is pmodes[] a fixed size?  I expected it to have num_scanouts elements.

> +};
> +\end{lstlisting}
> +
> +The response contains a list of per-scanout information.  The info
> +contains whether the scanout is enabled and what its preferred
> +position and size is.

What does "enabled" mean?

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