Re: [Qemu-devel] [PATCH] RFC: qxl: allow to specify head limit to qxl driver

[Gerd Hoffmann <kraxel@redhat.com>]

On Di, 2015-06-09 at 09:49 +0100, Frediano Ziglio wrote:
> This patch allow to limit number of heads using qxl driver. By default
> qxl driver is not limited on any kind on head use so can decide to use
> as much heads.

There is a hard limit of 16 monitors in the qxl device ...

> Main question and stop over are parameter name.

max_outputs please, to be consistent with upcoming virtio-vga.

> +    if (d->max_heads && d->max_heads <= 64) {
> +        rom->flags         = cpu_to_le64(QXL_ROM_FLAG_MAX_HEADS);
> +        rom->max_heads     = cpu_to_le16(d->max_heads);
> +    }

rom does already carry information about the heads.  How about simply
applying the limit when filling rom->client_monitors_config in
interface_client_monitors_config()?

No device changes, no driver changes, alot less trouble.

cheers,
  Gerd