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Commit 3c613a3b authored by Sebastian Reichel's avatar Sebastian Reichel Committed by Tomi Valkeinen
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drm/omap: fix incorrect union usage 



The DSI encoder sets dssdev->ops->dsi.set_config, which is stored at the
same offset as dssdev->ops->hdmi.set_hdmi_mode. The code in omap_encoder
only checks if dssdev->ops->hdmi.set_hdmi_mode is NULL. Due to the way
union works, it won't be NULL if dsi.set_config is set. This means
dsi_set_config will be called with config=hdmi_mode=false=NULL parameter
resulting in a NULL dereference. Also the dereference happens while
console is locked, so kernel hangs without any debug output without
"fb.lockless_register_fb=1" parameter.

This restructures the code, so that the HDMI mode is only configured
for HDMI output types.

Fixes: 83910ad3 ("drm/omap: Move most omap_dss_driver operations to omap_dss_device_ops")
Signed-off-by: default avatarSebastian Reichel <sebastian.reichel@collabora.com>
Tested-by: default avatarTony Lindgren <tony@atomide.com>
[tomi.valkeinen@ti.com: dropped the safeguard]
Signed-off-by: default avatarTomi Valkeinen <tomi.valkeinen@ti.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181121160916.22017-5-sebastian.reichel@collabora.com
parent 0a02d495

drivers/gpu/drm/omapdrm/omap_encoder.c

+33 −25
Original line number Diff line number Diff line
@@ -52,18 +52,45 @@ static const struct drm_encoder_funcs omap_encoder_funcs = { 
	.destroy = omap_encoder_destroy,

};



static void omap_encoder_mode_set(struct drm_encoder *encoder,

				  struct drm_display_mode *mode,

static void omap_encoder_hdmi_mode_set(struct drm_encoder *encoder,

				       struct drm_display_mode *adjusted_mode)

{

	struct drm_device *dev = encoder->dev;

	struct omap_encoder *omap_encoder = to_omap_encoder(encoder);

	struct omap_dss_device *dssdev = omap_encoder->output;

	struct drm_connector *connector;

	struct omap_dss_device *dssdev;

	struct videomode vm = { 0 };

	bool hdmi_mode;



	hdmi_mode = false;

	list_for_each_entry(connector, &dev->mode_config.connector_list, head) {

		if (connector->encoder == encoder) {

			hdmi_mode = omap_connector_get_hdmi_mode(connector);

			break;

		}

	}



	if (dssdev->ops->hdmi.set_hdmi_mode)

		dssdev->ops->hdmi.set_hdmi_mode(dssdev, hdmi_mode);



	if (hdmi_mode && dssdev->ops->hdmi.set_infoframe) {

		struct hdmi_avi_infoframe avi;

		int r;



		r = drm_hdmi_avi_infoframe_from_display_mode(&avi, adjusted_mode,

							     false);

		if (r == 0)

			dssdev->ops->hdmi.set_infoframe(dssdev, &avi);

	}

}



static void omap_encoder_mode_set(struct drm_encoder *encoder,

				  struct drm_display_mode *mode,

				  struct drm_display_mode *adjusted_mode)

{

	struct omap_encoder *omap_encoder = to_omap_encoder(encoder);

	struct omap_dss_device *dssdev;

	struct videomode vm = { 0 };



	drm_display_mode_to_videomode(adjusted_mode, &vm);



	/*
@@ -112,27 +139,8 @@ static void omap_encoder_mode_set(struct drm_encoder *encoder, 
	}



	/* Set the HDMI mode and HDMI infoframe if applicable. */

	hdmi_mode = false;

	list_for_each_entry(connector, &dev->mode_config.connector_list, head) {

		if (connector->encoder == encoder) {

			hdmi_mode = omap_connector_get_hdmi_mode(connector);

			break;

		}

	}



	dssdev = omap_encoder->output;



	if (dssdev->ops->hdmi.set_hdmi_mode)

		dssdev->ops->hdmi.set_hdmi_mode(dssdev, hdmi_mode);



	if (hdmi_mode && dssdev->ops->hdmi.set_infoframe) {

		struct hdmi_avi_infoframe avi;



		r = drm_hdmi_avi_infoframe_from_display_mode(&avi, adjusted_mode,

							     false);

		if (r == 0)

			dssdev->ops->hdmi.set_infoframe(dssdev, &avi);

	}

	if (omap_encoder->output->output_type == OMAP_DISPLAY_TYPE_HDMI)

		omap_encoder_hdmi_mode_set(encoder, adjusted_mode);

}



static void omap_encoder_disable(struct drm_encoder *encoder)