I get "Failed to read/write register index..." messages as well as several others. I believe that my mod hs addressed the usb power issue for my Pi, so the next step in the debug process is to figure out where the messages are coming from, what they mean and what to do about them.
This is where the message "Failed to read register index 0x00000114" is generated:
static int smsc95xx_read_reg(struct usbnet *dev, u32 index, u32 *data)
u32 *buf = kmalloc(4, GFP_KERNEL);
ret = usb_control_msg(dev->udev, usb_rcvctrlpipe(dev->udev, 0),
USB_DIR_IN | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
00, index, buf, 4, USB_CTRL_GET_TIMEOUT);
if (unlikely(ret < 0))
netdev_warn(dev->net, "Failed to read register index 0x%08x\n", index);
*data = *buf;
It is a warning from the driver, that it can't read a register at index 114(hex) which is according to smsc95xx.h is:
#define MII_ADDR (0x114)
NOT an ERROR, so the driver is not happy, but can continue, ...maybe.
Can it ever read index 0x114, or does this happen only under certain conditions?
What are the consequences of not being able to read it.
There seems to be another thread regarding this particular message:
http://www.raspberrypi.org/phpBB3/viewt ... 1&p=129570
As usual, the power is the first suspect.
With my moded Pi running debian I can run a speedtest of the Lan to http://www.2wire.com
(no java or flash) that returns 2Mbps and adds no messages to dmesg, but If I plug a usb mouse into my powered usb 2 hub connected to the Pi with a cable with the power line cut, I get a bunch of messages including 2 "Failed to read/write register index 0x00000114".
When repeated, this hangs the system until the mouse is unplugged, or, sometimes it doesn't.
The rootfs for my system is on a usb hdd, so lots and lots and lots of usb transactions going on all the time, especially when doing a network speed test.
IMHO, the real elephant in the room is dwc_otg, dwc_otg_common, and the Synaptics IP. ie. the usb host controller driver, and hardware.