Index: uspace/drv/ohci/root_hub.c
===================================================================
--- uspace/drv/ohci/root_hub.c	(revision cd4ae1e19104328a0283b82f5fa548a351b42bbd)
+++ uspace/drv/ohci/root_hub.c	(revision a146aa330fe2bdb9d3fd1f9b1910cb4d81ed09e4)
@@ -149,9 +149,7 @@
 
 
-static void usb_create_serialized_hub_descriptor(rh_t *instance,
-	uint8_t ** out_result,
-	size_t * out_size);
-
-static void rh_init_descriptors(rh_t *instance);
+static int create_serialized_hub_descriptor(rh_t *instance);
+
+static int rh_init_descriptors(rh_t *instance);
 
 static int process_get_port_status_request(rh_t *instance, uint16_t port,
@@ -164,6 +162,5 @@
 	usb_transfer_batch_t * request);
 
-static void create_interrupt_mask(rh_t *instance, void ** buffer,
-	size_t * buffer_size);
+static void create_interrupt_mask_in_instance(rh_t *instance);
 
 static int process_get_descriptor_request(rh_t *instance,
@@ -198,6 +195,5 @@
 static int process_ctrl_request(rh_t *instance, usb_transfer_batch_t *request);
 
-static int process_interrupt(rh_t *instance, usb_transfer_batch_t * request,
-    void * change_buffer, size_t buffe_size);
+static int process_interrupt_mask_in_instance(rh_t *instance, usb_transfer_batch_t * request);
 
 static bool is_zeros(void * buffer, size_t size);
@@ -213,9 +209,17 @@
 	instance->port_count =
 	    (instance->registers->rh_desc_a >> RHDA_NDS_SHIFT) & RHDA_NDS_MASK;
-	rh_init_descriptors(instance);
+	int opResult = rh_init_descriptors(instance);
+	if(opResult != EOK){
+		return opResult;
+	}
 	// set port power mode to no-power-switching
 	instance->registers->rh_desc_a |= RHDA_NPS_FLAG;
 	instance->unfinished_interrupt_transfer = NULL;
-	instance->interrupt_buffer = malloc((instance->port_count + 8)/8);
+	instance->interrupt_mask_size = (instance->port_count + 8)/8;
+	instance->interrupt_buffer = malloc(instance->interrupt_mask_size);
+	if(!instance->interrupt_buffer)
+		return ENOMEM;
+	
+
 	usb_log_info("OHCI root hub with %d ports.\n", instance->port_count);
 	return EOK;
@@ -240,19 +244,14 @@
 	} else if (request->ep->transfer_type == USB_TRANSFER_INTERRUPT) {
 		usb_log_info("Root hub got INTERRUPT packet\n");
-		void * buffer;
-		size_t buffer_size;
-		create_interrupt_mask(instance, &buffer,
-			&buffer_size);
-		if(is_zeros(buffer,buffer_size)){
-			usb_log_debug("no changes..");
-			instance->unfinished_interrupt_transfer=
-			    request;
+		create_interrupt_mask_in_instance(instance);
+		if(is_zeros(instance->interrupt_buffer,
+		    instance->interrupt_mask_size)){
+			usb_log_debug("no changes..\n");
+			instance->unfinished_interrupt_transfer = request;
 			//will be finished later
 		}else{
-			usb_log_debug("processing changes..");
-			process_interrupt(instance, request,
-			    buffer, buffer_size);
-		}
-		free(buffer);
+			usb_log_debug("processing changes..\n");
+			process_interrupt_mask_in_instance(instance, request);
+		}
 		opResult = EOK;
 	} else {
@@ -265,18 +264,18 @@
 /*----------------------------------------------------------------------------*/
 
-
+/**
+ * process interrupt on a hub
+ *
+ * If there is no pending interrupt transfer, nothing happens.
+ * @param instance
+ */
 void rh_interrupt(rh_t *instance) {
-	//usb_log_info("Whoa whoa wait, I`m not supposed to receive any "
-	//	"interrupts, am I?\n");
 	if(!instance->unfinished_interrupt_transfer){
 		return;
 	}
-	size_t size;
-	void * buffer;
-	create_interrupt_mask(instance, &buffer,
-			&size);
-	process_interrupt(instance,instance->unfinished_interrupt_transfer,
-	    buffer,size);
-	free(buffer);
+	usb_log_debug("finalizing interrupt transfer\n");
+	create_interrupt_mask_in_instance(instance);
+	process_interrupt_mask_in_instance(instance,
+	    instance->unfinished_interrupt_transfer);
 }
 /*----------------------------------------------------------------------------*/
@@ -289,17 +288,13 @@
  *
  * @param instance root hub instance
- * @param@out out_result pointer to resultant serialized descriptor
- * @param@out out_size size of serialized descriptor
- */
-static void usb_create_serialized_hub_descriptor(rh_t *instance,
-	uint8_t ** out_result,
-	size_t * out_size) {
-	//base size
-	size_t size = 7;
-	//variable size according to port count
-	size_t var_size = instance->port_count / 8 +
-		((instance->port_count % 8 > 0) ? 1 : 0);
-	size += 2 * var_size;
+ * @return error code
+ */
+static int create_serialized_hub_descriptor(rh_t *instance) {
+	size_t size = 7 +
+	    ((instance->port_count +7 )/ 8) * 2;
+	size_t var_size = (instance->port_count +7 )/ 8;
 	uint8_t * result = (uint8_t*) malloc(size);
+	if(!result) return ENOMEM;
+
 	bzero(result, size);
 	//size
@@ -330,6 +325,7 @@
 		result[7 + var_size + i] = 255;
 	}
-	(*out_result) = result;
-	(*out_size) = size;
+	instance->hub_descriptor = result;
+	instance->descriptor_size = size;
+	return EOK;
 }
 /*----------------------------------------------------------------------------*/
@@ -340,6 +336,7 @@
  * be initialized only once per hub.
  * @instance root hub instance
- */
-static void rh_init_descriptors(rh_t *instance) {
+ * @return error code
+ */
+static int rh_init_descriptors(rh_t *instance) {
 	memcpy(&instance->descriptors.device, &ohci_rh_device_descriptor,
 		sizeof (ohci_rh_device_descriptor)
@@ -348,17 +345,20 @@
 	memcpy(&descriptor, &ohci_rh_conf_descriptor,
 		sizeof (ohci_rh_conf_descriptor));
-	uint8_t * hub_descriptor;
-	size_t hub_desc_size;
-	usb_create_serialized_hub_descriptor(instance, &hub_descriptor,
-		&hub_desc_size);
-
+
+	int opResult = create_serialized_hub_descriptor(instance);
+	if(opResult != EOK){
+		return opResult;
+	}
 	descriptor.total_length =
 		sizeof (usb_standard_configuration_descriptor_t) +
 		sizeof (usb_standard_endpoint_descriptor_t) +
 		sizeof (usb_standard_interface_descriptor_t) +
-		hub_desc_size;
+		instance->descriptor_size;
 
 	uint8_t * full_config_descriptor =
 		(uint8_t*) malloc(descriptor.total_length);
+	if(!full_config_descriptor){
+		return ENOMEM;
+	}
 	memcpy(full_config_descriptor, &descriptor, sizeof (descriptor));
 	memcpy(full_config_descriptor + sizeof (descriptor),
@@ -370,8 +370,9 @@
 		sizeof (ohci_rh_iface_descriptor) +
 		sizeof (ohci_rh_ep_descriptor),
-		hub_descriptor, hub_desc_size);
-
+		instance->hub_descriptor, instance->descriptor_size);
+	
 	instance->descriptors.configuration = full_config_descriptor;
 	instance->descriptors.configuration_size = descriptor.total_length;
+	return EOK;
 }
 /*----------------------------------------------------------------------------*/
@@ -464,19 +465,13 @@
  * bit i indicates change on i`th port (i>0). For more info see
  * Hub and Port status bitmap specification in USB specification
- * (chapter 11.13.4)
- * @param instance root hub instance
- * @param@out buffer pointer to created interrupt mas
- * @param@out buffer_size size of created interrupt mask
- */
-static void create_interrupt_mask(rh_t *instance, void ** buffer,
-	size_t * buffer_size) {
-	int bit_count = instance->port_count + 1;
-	(*buffer_size) = (bit_count+7 / 8);
-
-	(*buffer) = instance->interrupt_buffer;//malloc(*buffer_size);
-	uint8_t * bitmap = (uint8_t*) (*buffer);
+ * (chapter 11.13.4).
+ * Uses instance`s interrupt buffer to store the interrupt information.
+ * @param instance root hub instance
+ */
+static void create_interrupt_mask_in_instance(rh_t * instance) {
+	uint8_t * bitmap = (uint8_t*) (instance->interrupt_buffer);
 	uint32_t mask = (1 << (USB_HUB_FEATURE_C_HUB_LOCAL_POWER + 16))
 		| (1 << (USB_HUB_FEATURE_C_HUB_OVER_CURRENT + 16));
-	bzero(bitmap, (*buffer_size));
+	bzero(bitmap, instance->interrupt_mask_size);
 	if (instance->registers->rh_status & mask) {
 		bitmap[0] = 1;
@@ -509,13 +504,10 @@
 	const uint16_t setup_request_value = setup_request->value_high;
 	//(setup_request->value_low << 8);
-	bool del = false;
 	switch (setup_request_value) {
 		case USB_DESCTYPE_HUB:
 		{
-			uint8_t * descriptor;
-			usb_create_serialized_hub_descriptor(
-				instance, &descriptor, &size);
-			result_descriptor = descriptor;
-			if (result_descriptor) del = true;
+			usb_log_debug("USB_DESCTYPE_HUB\n");
+			result_descriptor = instance->hub_descriptor;
+			size = instance->descriptor_size;
 			break;
 		}
@@ -568,6 +560,4 @@
 	request->transfered_size = size;
 	memcpy(request->data_buffer, result_descriptor, size);
-	if (del)
-		free(result_descriptor);
 	return EOK;
 }
@@ -895,14 +885,11 @@
  * @param instance hub instance
  * @param request batch request to be processed
- * @param change_buffer chages on hub
- * @param buffer_size size of change buffer
  *
  * @return
  */
-static int process_interrupt(rh_t *instance, usb_transfer_batch_t * request,
-    void * change_buffer, size_t buffe_size){
-	create_interrupt_mask(instance, &change_buffer,
-	    &(request->transfered_size));
-	memcpy(request->data_buffer, change_buffer,request->transfered_size);
+static int process_interrupt_mask_in_instance(rh_t *instance, usb_transfer_batch_t * request){
+	memcpy(request->data_buffer, instance->interrupt_buffer,
+	    instance->interrupt_mask_size);
+	request->transfered_size = instance->interrupt_mask_size;
 	instance->unfinished_interrupt_transfer = NULL;
 	usb_transfer_batch_finish_error(request, EOK);
Index: uspace/drv/ohci/root_hub.h
===================================================================
--- uspace/drv/ohci/root_hub.h	(revision cd4ae1e19104328a0283b82f5fa548a351b42bbd)
+++ uspace/drv/ohci/root_hub.h	(revision a146aa330fe2bdb9d3fd1f9b1910cb4d81ed09e4)
@@ -59,7 +59,16 @@
 	 *
 	 * This is allocated when initializing instance, so that memory
-	 * allocation is not needed when processing request.
+	 * allocation is not needed when processing request. Buffer is used for
+	 * interrupt bitmask.
 	 */
 	uint8_t * interrupt_buffer;
+	/** size of interrupt buffer */
+	size_t interrupt_mask_size;
+	/** instance`s descriptor*/
+	uint8_t * hub_descriptor;
+	/** size of hub descriptor */
+	size_t descriptor_size;
+
+
 } rh_t;
 
Index: uspace/drv/usbhub/main.c
===================================================================
--- uspace/drv/usbhub/main.c	(revision cd4ae1e19104328a0283b82f5fa548a351b42bbd)
+++ uspace/drv/usbhub/main.c	(revision a146aa330fe2bdb9d3fd1f9b1910cb4d81ed09e4)
@@ -55,9 +55,16 @@
 };
 
-
+/**
+ * usb hub driver operations
+ *
+ * The most important one is add_device, which is set to usb_hub_add_device.
+ */
 static usb_driver_ops_t usb_hub_driver_ops = {
 	.add_device = usb_hub_add_device
 };
 
+/**
+ * hub endpoints, excluding control endpoint
+ */
 static usb_endpoint_description_t *usb_hub_endpoints[] = {
 	&hub_status_change_endpoint_description,
@@ -65,4 +72,7 @@
 };
 
+/**
+ * static usb hub driver information
+ */
 static usb_driver_t usb_hub_driver = {
 	.name = NAME,
Index: uspace/drv/usbhub/ports.c
===================================================================
--- uspace/drv/usbhub/ports.c	(revision cd4ae1e19104328a0283b82f5fa548a351b42bbd)
+++ uspace/drv/usbhub/ports.c	(revision a146aa330fe2bdb9d3fd1f9b1910cb4d81ed09e4)
@@ -167,5 +167,4 @@
 
 	//close address
-	//if (hub->attached_devs[port].address != 0) {
 	if(hub->ports[port].attached_device.address >= 0){
 		/*uncomment this code to use it when DDF allows device removal
@@ -182,5 +181,4 @@
 		 */
 	} else {
-		// TODO: is this really reason to print a warning?
 		usb_log_warning("Device removed before being registered.\n");
 
Index: uspace/drv/usbhub/usbhub.c
===================================================================
--- uspace/drv/usbhub/usbhub.c	(revision cd4ae1e19104328a0283b82f5fa548a351b42bbd)
+++ uspace/drv/usbhub/usbhub.c	(revision a146aa330fe2bdb9d3fd1f9b1910cb4d81ed09e4)
@@ -73,6 +73,4 @@
 
 
-/// \TODO malloc checking
-
 //*********************************************
 //
@@ -248,4 +246,7 @@
 	hub_info->ports = malloc(
 	    sizeof (usb_hub_port_t) * (hub_info->port_count + 1));
+	if(!hub_info->ports){
+		return ENOMEM;
+	}
 	size_t port;
 	for (port = 0; port < hub_info->port_count + 1; ++port) {
@@ -255,4 +256,14 @@
 		usb_log_debug("is_power_switched\n");
 		
+		if(!has_individual_port_powering){
+			usb_log_debug("!has_individual_port_powering\n");
+			opResult = usb_hub_set_feature(hub_info->control_pipe,
+			    USB_HUB_FEATURE_C_HUB_LOCAL_POWER);
+			if (opResult != EOK) {
+				usb_log_error("cannot power hub: %s\n",
+				    str_error(opResult));
+			}
+		}
+
 		for (port = 1; port <= hub_info->port_count; ++port) {
 			usb_log_debug("Powering port %zu.\n",port);
@@ -264,15 +275,7 @@
 			}
 		}
-		if(!has_individual_port_powering){
-			usb_log_debug("!has_individual_port_powering\n");
-			opResult = usb_hub_set_feature(hub_info->control_pipe,
-			    USB_HUB_FEATURE_C_HUB_LOCAL_POWER);
-			if (opResult != EOK) {
-				usb_log_error("cannot power hub: %s\n",
-				    str_error(opResult));
-			}
-		}
+		
 	}else{
-		usb_log_debug("!is_power_switched\n");
+		usb_log_debug("!is_power_switched, not going to be powered\n");
 	}
 	usb_log_debug2("freeing data\n");