[PATCH] qxl: add a connector property to denote hotplug should rescan modes.

[Daniel Vetter]

On Fri, Oct 11, 2013 at 11:05:00AM +1000, Dave Airlie wrote:
> From: Dave Airlie <airlied at redhat.com>
> 
> So GNOME userspace has an issue with when it rescans for modes on hotplug
> events, if the monitor has no EDID it assumes that nothing has changed on
> EDID as with real hw we'd never have new modes without a new EDID, and they
> kind off rely on the behaviour now, however with virtual GPUs we would
> like to rescan the modes and get a new preferred mode on hotplug events
> to handle dynamic guest resizing (where you resize the host window and the
> guest resizes with it).
> 
> This is a simple property we can make userspace watch for to trigger new
> behaviour based on it, and can be used to replaced EDID hacks in virtual
> drivers.
> 
> Signed-off-by: Dave Airlie <airlied at redhat.com>

There's the related problem that we kinda don't tell userspace which
connectors exactly changed when sending out a hotplug event. We could
solve both issues with a hotplug_sequence counter that increments on any
change. Probably more work though ;-)
-Daniel

> ---
>  drivers/gpu/drm/qxl/qxl_display.c | 18 ++++++++++++++++++
>  drivers/gpu/drm/qxl/qxl_drv.h     |  2 ++
>  2 files changed, 20 insertions(+)
> 
> diff --git a/drivers/gpu/drm/qxl/qxl_display.c b/drivers/gpu/drm/qxl/qxl_display.c
> index 835caba..d83a0b7 100644
> --- a/drivers/gpu/drm/qxl/qxl_display.c
> +++ b/drivers/gpu/drm/qxl/qxl_display.c
> @@ -835,8 +835,21 @@ static const struct drm_encoder_funcs qxl_enc_funcs = {
>  	.destroy = qxl_enc_destroy,
>  };
>  
> +static int qxl_mode_create_hotplug_mode_update_property(struct qxl_device *qdev)
> +{
> +	if (qdev->hotplug_mode_update_property)
> +		return 0;
> +
> +	qdev->hotplug_mode_update_property =
> +		drm_property_create_range(qdev->ddev, DRM_MODE_PROP_IMMUTABLE,
> +					  "hotplug_mode_update", 0, 1);
> +
> +	return 0;
> +}
> +
>  static int qdev_output_init(struct drm_device *dev, int num_output)
>  {
> +	struct qxl_device *qdev = dev->dev_private;
>  	struct qxl_output *qxl_output;
>  	struct drm_connector *connector;
>  	struct drm_encoder *encoder;
> @@ -863,6 +876,8 @@ static int qdev_output_init(struct drm_device *dev, int num_output)
>  	drm_encoder_helper_add(encoder, &qxl_enc_helper_funcs);
>  	drm_connector_helper_add(connector, &qxl_connector_helper_funcs);
>  
> +	drm_object_attach_property(&connector->base,
> +				   qdev->hotplug_mode_update_property, 0);
>  	drm_sysfs_connector_add(connector);
>  	return 0;
>  }
> @@ -975,6 +990,9 @@ int qxl_modeset_init(struct qxl_device *qdev)
>  	qdev->ddev->mode_config.max_height = 8192;
>  
>  	qdev->ddev->mode_config.fb_base = qdev->vram_base;
> +
> +	qxl_mode_create_hotplug_mode_update_property(qdev);
> +
>  	for (i = 0 ; i < qxl_num_crtc; ++i) {
>  		qdev_crtc_init(qdev->ddev, i);
>  		qdev_output_init(qdev->ddev, i);
> diff --git a/drivers/gpu/drm/qxl/qxl_drv.h b/drivers/gpu/drm/qxl/qxl_drv.h
> index 41d22ed..7bda32f 100644
> --- a/drivers/gpu/drm/qxl/qxl_drv.h
> +++ b/drivers/gpu/drm/qxl/qxl_drv.h
> @@ -323,6 +323,8 @@ struct qxl_device {
>  	struct work_struct gc_work;
>  
>  	struct work_struct fb_work;
> +
> +	struct drm_property *hotplug_mode_update_property;
>  };
>  
>  /* forward declaration for QXL_INFO_IO */
> -- 
> 1.8.3.1
> 
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-- 
Daniel Vetter
Software Engineer, Intel Corporation
+41 (0) 79 365 57 48 - http://blog.ffwll.ch