Hi Alexander,
Thanks for your comments!
On Tuesday, June 14, 2016 5:54 PM, Alexander wrote:
+static struct +device_node *detect_hdmi_connection(struct fsl_dcu_drm_device +*fsl_dev) {
- struct device_node *remote_port;
- struct of_endpoint *ep;
- struct device_node *ep_node;
- int ret;
- struct device_node *parent = fsl_dev->dev->of_node;
- ep = devm_kzalloc(fsl_dev->dev,
sizeof(struct of_endpoint), GFP_KERNEL);- if (!ep)
return NULL;- ep_node = devm_kzalloc(fsl_dev->dev,
sizeof(struct device_node), GFP_KERNEL);- if (!ep_node)
return NULL;- ep_node = of_graph_get_next_endpoint(parent, NULL);
^^^^^^^You overwrite the pointer to previously allocated memory.
Woops! I will fix that.
- if (!ep_node)
goto error;- ret = of_graph_parse_endpoint(ep_node, ep);
- if (ret) {
of_node_put(ep_node);goto error;- }
- remote_port = of_graph_get_remote_port_parent(ep->local_node);
- if (!remote_port)
goto error;- return remote_port;
+error:
- devm_kfree(ep);
- devm_kfree(ep_node);
- return NULL;
+}
So, unless you hit the error label the memory allocated using devm_kzalloc stays around until the device is removed. I don't know DRM internals much, but can load (within drm_driver) be called multiple times during device lifetime?
I think load called once every drm_device registered.
This would allocate memory each time it is called. Why not allocate 'ep' on stack while ep_node don't need allocation at all, no?
Yep, allocate 'ep' on stack is better, and error label can be removed.
diff --git a/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_kms.c b/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_kms.c index c564ec6..658bc92 100644 --- a/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_kms.c +++ b/drivers/gpu/drm/fsl-dcu/fsl_dcu_drm_kms.c @@ -17,10 +17,18 @@ #include "fsl_dcu_drm_crtc.h" #include "fsl_dcu_drm_drv.h"
+static void fsl_dcu_drm_output_poll_changed(struct drm_device *dev) {
- struct fsl_dcu_drm_device *fsl_dev = dev->dev_private;
- drm_fbdev_cma_hotplug_event(fsl_dev->fbdev);
+}
static const struct drm_mode_config_funcs fsl_dcu_drm_mode_config_funcs = { .atomic_check =
drm_atomic_helper_check,
.atomic_commit = drm_atomic_helper_commit, .fb_create = drm_fb_cma_create,
- .output_poll_changed = fsl_dcu_drm_output_poll_changed,
};
int fsl_dcu_drm_modeset_init(struct fsl_dcu_drm_device *fsl_dev) @@ -47,6 +55,14 @@ int fsl_dcu_drm_modeset_init(struct fsl_dcu_drm_device *fsl_dev) if (ret) goto fail_connector;
- ret = fsl_dcu_drm_hdmienc_create(fsl_dev, &fsl_dev->crtc);
- if (ret)
DRM_ERROR("Failed to create HDMI encoder\n");- ret = fsl_dcu_drm_hdmienc_attach_bridge(fsl_dev);
- if (ret)
DRM_ERROR("Failed to attach HDMI bridge\n");Are those really errors? What about setups without any HDMI bridge at all? I
If device-tree is given, it just print error message, and HDMI don't display, that all. RGB-LCD can display normally.
If device-tree is not given, attach bridge will return when detecting HDMI connection. I think this should also be checked within " hdmienc_create ", or encoder will be allocated anyway. Will fix that next version.
would conside it an error if a bridge is given in device-tree but detecting or whatsoever fails for some reason.
Yep, I just think that two function's return value should be handled, so put the error message here. Maybe return value check should be dropped. What do you think?
Best Regards, Meng