Date:   Mon, 6 Mar 2023 08:32:30 +0100
From:   Gerd Hoffmann <kraxel@redhat.com>
To:     Dmitry Osipenko <dmitry.osipenko@collabora.com>
Cc:     Rob Clark <robdclark@gmail.com>,
        Gurchetan Singh <gurchetansingh@chromium.org>,
        Chia-I Wu <olvaffe@gmail.com>,
        Ryan Neph <ryanneph@chromium.org>,
        dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org,
        Javier Martinez Canillas <javierm@redhat.com>,
        David Airlie <airlied@redhat.com>, kernel@collabora.com,
        virtualization@lists.linux-foundation.org
Subject: Re: [PATCH v1] drm/virtio: Fix handling CONFIG_DRM_VIRTIO_GPU_KMS
 option
Message-ID: <20230306073230.cka4j44sdteqrpao@sirius.home.kraxel.org>
References: <20230304220510.964715-1-dmitry.osipenko@collabora.com>
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In-Reply-To: <20230304220510.964715-1-dmitry.osipenko@collabora.com>
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> +++ b/drivers/gpu/drm/virtio/virtgpu_kms.c
> @@ -45,9 +45,11 @@ static void virtio_gpu_config_changed_work_func(struct work_struct *work)
>  	if (events_read & VIRTIO_GPU_EVENT_DISPLAY) {
>  		if (vgdev->has_edid)
>  			virtio_gpu_cmd_get_edids(vgdev);
> -		virtio_gpu_cmd_get_display_info(vgdev);
> -		virtio_gpu_notify(vgdev);
> -		drm_helper_hpd_irq_event(vgdev->ddev);
> +		if (vgdev->num_scanouts) {
> +			virtio_gpu_cmd_get_display_info(vgdev);
> +			virtio_gpu_notify(vgdev);
> +			drm_helper_hpd_irq_event(vgdev->ddev);
> +		}

I'd suggest to make the edid lines conditional too.

> -	if (IS_ENABLED(CONFIG_DRM_VIRTIO_GPU_KMS) || !vgdev->num_scanouts) {
> +	if (!IS_ENABLED(CONFIG_DRM_VIRTIO_GPU_KMS) || !vgdev->num_scanouts) {
>  		DRM_INFO("KMS disabled\n");
>  		vgdev->num_scanouts = 0;
>  		vgdev->has_edid = false;

Doesn't make a difference because has_edid gets set to false here,
but IMHO it is less confusing that way.

take care,
  Gerd