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Date:   Fri, 5 Oct 2018 17:55:05 +0200
From:   Gerd Hoffmann <kraxel@redhat.com>
To:     Christophe de Dinechin <cdupontd@redhat.com>
Cc:     Daniel Vetter <daniel@ffwll.ch>, kvm@vger.kernel.org,
        "Michael S. Tsirkin" <mst@redhat.com>,
        David Airlie <airlied@linux.ie>,
        open list <linux-kernel@vger.kernel.org>,
        Jason Wang <jasowang@redhat.com>, virtio-dev@redhat.com,
        dri-devel@lists.freedesktop.org,
        "open list:VIRTIO GPU DRIVER" 
        <virtualization@lists.linux-foundation.org>
Subject: Re: [PATCH v2] virtio-gpu: add VIRTIO_GPU_F_EDID feature
Message-ID: <20181005155505.phmi65hvu2rkulkm@sirius.home.kraxel.org>
References: <20181005125154.19824-1-kraxel@redhat.com>
 <1BA83F18-87E5-4B01-A2D9-01777078B637@redhat.com>
 <20181005144127.GE31561@phenom.ffwll.local>
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  Hi,

> >>> +/* VIRTIO_GPU_RESP_OK_EDID */
> >>> +struct virtio_gpu_resp_edid {
> >>> +	struct virtio_gpu_ctrl_hdr hdr;
> >>> +	__le32 scanout;
> >>> +	__le32 size;
> >>> +	__u8 edid[1024];
> >> 
> >> Wouldn’t it be enough to stick to EDID 2.0 (256 bytes)?
> >> 
> >> If not, maybe add comment to explain why you chose 1024.
> > 
> > EDID in the wild can be up to 512 bytes.
> 
> Does this return a physical EDID? I thought it would be made-up by virtio-gpu.

Well, edid has extensions, so it can become pretty large in theory, and
I've figured it would be a good idea to leave some room just in case.
It should be a rather infrequent operation, so the unused buffer space
should not hurt much.

Yes, it will be a edid generated by qemu.  The current generator code will
use at most 256 bytes.

cheers,
  Gerd