[Spice-devel] [RFC/POC PATCH spice-protocol 02/16] Create a version 2 of the VDAgentMonitorsConfig message

[Jonathon Jongsma]

On Tue, 2018-06-05 at 17:30 +0200, Lukáš Hrázký wrote:
> To keep compatibility with old endpoints (any of client, server,
> vd_agent), we need to copy the message to add the output_id field.
> 
> The output_id is the guest-side id of the xrandr output (to be
> precise,
> it is the index in the list of xrandr outputs) that is set in the
> monitors config messages by the streaming agent. It is later used in
> the
> guest by vd_agent for mouse input and possibly monitors_config
> (enabling/disabling monitors and setting the resolution/position of
> monitors).
> 
> Signed-off-by: Lukáš Hrázký <lhrazky at redhat.com>
> ---
>  spice/vd_agent.h | 27 +++++++++++++++++++++++++++
>  1 file changed, 27 insertions(+)
> 
> diff --git a/spice/vd_agent.h b/spice/vd_agent.h
> index dda7044..05c9c40 100644
> --- a/spice/vd_agent.h
> +++ b/spice/vd_agent.h
> @@ -154,6 +154,33 @@ typedef struct SPICE_ATTR_PACKED
> VDAgentMonitorsConfig {
>      VDAgentMonConfig monitors[0];
>  } VDAgentMonitorsConfig;
>  
> +typedef struct SPICE_ATTR_PACKED VDAgentMonConfigV2 {
> +    /* The output_id is the guest-side id of the xrandr output (to
> be precise,
> +     * it is the index in the list of xrandr outputs) that is set in
> the
> +     * monitors config messages by the streaming agent. It is later
> used in the
> +     * guest by vd_agent for mouse input and possibly
> monitors_config
> +     * (enabling/disabling monitors and setting the
> resolution/position of
> +     * monitors).
> +    */
> +    uint32_t output_id;
> +    /*
> +     * Note a width and height of 0 can be used to indicate a
> disabled
> +     * monitor, this may only be used with agents with the
> +     * VD_AGENT_CAP_SPARSE_MONITORS_CONFIG capability.
> +     */
> +    uint32_t height;
> +    uint32_t width;
> +    uint32_t depth;
> +    int32_t x;
> +    int32_t y;
> +} VDAgentMonConfigV2;

You might put the output_id at the end of the struct instead of the
beginning so that the beginning of the struct is identical to the old
version?

Or maybe just extend it rather than copying the old struct?

typedef struct SPICE_ATTR_PACKED VDAgentMonConfigV2 {
  VDAgentMonConfig base;
  uin32_t output_id;
} ....

Maybe that makes it a too awkward to use though...


> +
> +typedef struct SPICE_ATTR_PACKED VDAgentMonitorsConfigV2 {
> +    uint32_t num_of_monitors;
> +    uint32_t flags;
> +    VDAgentMonConfigV2 monitors[0];
> +} VDAgentMonitorsConfigV2;
> +
>  enum {
>      VD_AGENT_DISPLAY_CONFIG_FLAG_DISABLE_WALLPAPER = (1 << 0),
>      VD_AGENT_DISPLAY_CONFIG_FLAG_DISABLE_FONT_SMOOTH = (1 << 1),