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. The new function also has a safe-guard directly
before accessing the union, that can be optimized away by the compiler
when the function is inlined and HDMI type has already been checked.
Fixes: 83910ad3f51fb ("drm/omap: Move most omap_dss_driver operations to omap_dss_device_ops")
Signed-off-by: Sebastian Reichel <sebastian.reichel@xxxxxxxxxxxxx>
---
drivers/gpu/drm/omapdrm/omap_encoder.c | 62 +++++++++++++++-----------
1 file changed, 37 insertions(+), 25 deletions(-)
diff --git a/drivers/gpu/drm/omapdrm/omap_encoder.c b/drivers/gpu/drm/omapdrm/omap_encoder.c
index 32bbe3a80e7d..f356821cd078 100644
--- a/drivers/gpu/drm/omapdrm/omap_encoder.c
+++ b/drivers/gpu/drm/omapdrm/omap_encoder.c
@@ -52,17 +52,48 @@ 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;
+ }
+ }
+
+ /* safe-guard for accessing dssdev->ops->hdmi union */
+ if (dssdev->output_type != OMAP_DISPLAY_TYPE_HDMI)
+ return;
+
+ 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 +143,8 @@ 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)
--
2.19.1
_______________________________________________
dri-devel mailing list
dri-devel@xxxxxxxxxxxxxxxxxxxxx
https://lists.freedesktop.org/mailman/listinfo/dri-devel
