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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: 83910ad3f5 ("drm/omap: Move most omap_dss_driver operations to omap_dss_device_ops")
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
Tested-by: Tony Lindgren <tony@atomide.com>
[tomi.valkeinen@ti.com: dropped the safeguard]
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20181121160916.22017-5-sebastian.reichel@collabora.com
hifive-unleashed-5.1
Sebastian Reichel 2018-11-21 17:09:14 +01:00 committed by Tomi Valkeinen
parent 0a02d49553
commit 3c613a3bdd
1 changed files with 33 additions and 25 deletions
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58
drivers/gpu/drm/omapdrm/omap_encoder.c
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@ -52,17 +52,44 @@ static const struct drm_encoder_funcs omap_encoder_funcs = {
.destroy = omap_encoder_destroy,
};
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;
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 drm_device *dev = encoder->dev;
struct omap_encoder *omap_encoder = to_omap_encoder(encoder);
struct drm_connector *connector;
struct omap_dss_device *dssdev;
struct videomode vm = { 0 };
bool hdmi_mode;
int r;
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)