Re: [Qemu-devel] [PATCH] qxl: don't render stuff when the vm is stopped.

[Yonit Halperin]

Hi,
On 02/15/2012 03:11 PM, Gerd Hoffmann wrote:
> This patch fixes the local qxl renderer to not kick spice-server in case
> the vm is stopped.  First it is pointless because we render evevything
> when the vm is stopped.  Thus there is nothing to render anyway because
> a stopped guest can hardly queue more commands.
hmm...When the vm is stopped we render only commands that we already 
read. We don't do more reading from the command ring. So there may be 
other pending commands that were not rendered.
That is why I suggested allowing rendering when the vm is stopped. But 
not allowing it during loading the vm during migration.

Regards,
Yonit.
 Second we avoid
> triggering an assert in spice-server.
>
> With this patch applied it is possible to take screen shots (via
> screendump monitor command) from a qxl gpu even in case the guest
> is stopped.
>
> Signed-off-by: Gerd Hoffmann<address@hidden>
> ---
>   hw/qxl-render.c |   12 +++++-------
>   1 files changed, 5 insertions(+), 7 deletions(-)
>
> diff --git a/hw/qxl-render.c b/hw/qxl-render.c
> index 133d093..7084143 100644
> --- a/hw/qxl-render.c
> +++ b/hw/qxl-render.c
> @@ -121,19 +121,17 @@ void qxl_render_update(PCIQXLDevice *qxl)
>           dpy_resize(vga->ds);
>       }
>
> -    if (!qxl->guest_primary.commands) {
> -        return;
> -    }
> -    qxl->guest_primary.commands = 0;
> -
>       update.left   = 0;
>       update.right  = qxl->guest_primary.surface.width;
>       update.top    = 0;
>       update.bottom = qxl->guest_primary.surface.height;
>
>       memset(dirty, 0, sizeof(dirty));
> -    qxl_spice_update_area(qxl, 0,&update,
> -                          dirty, ARRAY_SIZE(dirty), 1, QXL_SYNC);
> +    if (runstate_is_running()&&  qxl->guest_primary.commands) {
> +        qxl->guest_primary.commands = 0;
> +        qxl_spice_update_area(qxl, 0,&update,
> +                              dirty, ARRAY_SIZE(dirty), 1, QXL_SYNC);
> +    }
>       if (redraw) {
>           memset(dirty, 0, sizeof(dirty));
>           dirty[0] = update;