Re: serial/mxs-auart: Unable to get interrupt counter from user space

[Greg KH <gregkh@linuxfoundation.org>]

On Sat, Jun 23, 2012 at 09:19:40PM +0200, Stefan Wahren wrote:
> Hello,
> 
> i'm using Linux 2.6.35 at ARM and i experience the following issue
> with the mxs-auart (App UART). If i transmit and receive data over
> the serial port (using mxs-auart), all the interrupt counter (RX,
> TX, frame, parity, break) accessed from user space (ioctl with
> TIOCGICOUNT or /proc/tty/driver/auart) are zero.
> 
> Here is the scenario to reproduce the problem:
> 
> 1. echoing some characters to the uart device
> 2. fetch the statistics from proc-Filesystem
> 
> Expected results: transmit counter greater than zero
> 
> Observed results: transmit counter is always zero
> 
> The same szenario on the mxs-duart (Debug UART) doesn't show this problem.
> 
> Is this a bug in mxs-auart or just not implemented?

We disabled the transmit counter from being displayed a while ago for
security reasons, perhaps that is what you are seeing?

Also, you do realize just how old 2.6.35 really is, right?

thanks,

greg k-h