# Debugging FAQ
This page details various common questions people have about troubleshooting their keyboards.
# Debug Console
## `hid_listen` Can't Recognize Device
When debug console of your device is not ready you will see like this:
```
Waiting for device:.........
```
once the device is plugged in then *hid_listen* finds it you will get this message:
```
Waiting for new device:.........................
Listening:
```
If you can't get this 'Listening:' message try building with `CONSOLE_ENABLE=yes` in [Makefile]
You may need privilege to access the device on OS like Linux.
- try `sudo hid_listen`
## Can't Get Message on Console
Check:
- *hid_listen* finds your device. See above.
- Enable debug with pressing **Magic**+d. See [Magic Commands](https://github.com/tmk/tmk_keyboard#magic-commands).
- set `debug_enable=true`. See [Testing and Debugging](newbs_testing_debugging.md#debugging)
- try using 'print' function instead of debug print. See **common/print.h**.
- disconnect other devices with console function. See [Issue #97](https://github.com/tmk/tmk_keyboard/issues/97).
## Linux or UNIX Like System Requires Super User Privilege
Just use 'sudo' to execute *hid_listen* with privilege.
```
$ sudo hid_listen
```
Or add an *udev rule* for TMK devices with placing a file in rules dir/*
ChibiOS - Copyright (C) 2006..2016 Giovanni Di Sirio
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
*/
/*
Concepts and parts of this file have been contributed by Fabio Utzig,
chvprintf() added by Brent Roman.
*/
/**
* @file chprintf.c
* @brief Mini printf-like functionality.
*
* @addtogroup chprintf
* @{
*/
#include "hal.h"
#include "chprintf.h"
#include "memstreams.h"
#define MAX_FILLER 11
#define FLOAT_PRECISION 9
static char *long_to_string_with_divisor(char *p,
long num,
unsigned radix,
long divisor) {
int i;
char *q;
long l, ll;
l = num;
if (divisor == 0) {
ll = num;
} else {
ll = divisor;
}
q = p + MAX_FILLER;
do {
i = (int)(l % radix);
i += '0';
if (i > '9')
i += 'A' - '0' - 10;
*--q = i;
l /= radix;
} while ((ll /= radix) != 0);
i = (int)(p + MAX_FILLER - q);
do
*p++ = *q++;
while (--i);
return p;
}
static char *ch_ltoa(char *p, long num, unsigned radix) {
return long_to_string_with_divisor(p, num, radix, 0);
}
#if CHPRINTF_USE_FLOAT
static const long pow10[FLOAT_PRECISION] = {
10, 100, 1000, 10000, 100000, 1000000, 10000000, 100000000, 1000000000
};
static char *ftoa(char *p, double num, unsigned long precision) {
long l;
if ((precision == 0) || (precision > FLOAT_PRECISION))
precision = FLOAT_PRECISION;
precision = pow10[precision - 1];
l = (long)num;
p = long_to_string_with_divisor(p, l, 10, 0);
*p++ = '.';
l = (long)((num - l) * precision);
return long_to_string_with_divisor(p, l, 10, precision / 10);
}
#endif
/**
* @brief System formatted output function.
* @details This function implements a minimal @p vprintf()-like functionality
* with output on a @p BaseSequentialStream.
* The general parameters format is: %[-][width|*][.precision|*][l|L]p.
* The following parameter types (p) are supported:
* - <b>x</b> hexadecimal integer.
* - <b>X</b> hexadecimal long.
* - <b>o</b> octal integer.
* - <b>O</b> octal long.
* - <b>d</b> decimal signed integer.
* - <b>D</b> decimal signed long.
* - <b>u</b> decimal unsigned integer.
* - <b>U</b> decimal unsigned long.
* - <b>c</b> character.
* - <b>s</b> string.
* .
*
* @param[in] chp pointer to a @p BaseSequentialStream implementing object
* @param[in] fmt formatting string
* @param[in] ap list of parameters
* @return The number of bytes that would have been
* written to @p chp if no stream error occurs
*
* @api
*/
int chvprintf(BaseSequentialStream *chp, const char *fmt, va_list ap) {
char *p, *s, c, filler;
int i, precision, width;
int n = 0;
bool is_long, left_align;
long l;
#if CHPRINTF_USE_FLOAT
float f;
char tmpbuf[2*MAX_FILLER + 1];
#else
char tmpbuf[MAX_FILLER + 1];
#endif
while (true) {
c = *fmt++;
if (c == 0)
return n;
if (c != '%') {
streamPut(chp, (uint8_t)c);
n++;
continue;
}
p = tmpbuf;
s = tmpbuf;
left_align = FALSE;
if (*fmt == '-') {
fmt++;
left_align = TRUE;
}
filler = ' ';
if (*fmt == '0') {
fmt++;
filler = '0';
}
width = 0;
while (TRUE) {
c = *fmt++;
if (c >= '0' && c <= '9')
c -= '0';
else if (c == '*')
c = va_arg(ap, int);
else
break;
width = width * 10 + c;
}
precision = 6;
if (c == '.') {
precision = 0;
while (TRUE) {
c = *fmt++;
if (c >= '0' && c <= '9')
c -= '0';
else if (c == '*')
c = va_arg(ap, int);
else
break;
precision *= 10;
precision += c;
}
}
/* Long modifier.*/
if (c == 'l' || c == 'L') {
is_long = TRUE;
if (*fmt)
c = *fmt++;
}
else
is_long = (c >= 'A') && (c <= 'Z');
/* Command decoding.*/
switch (c) {
case 'c':
filler = ' ';
*p++ = va_arg(ap, int);
break;
case 's':
filler = ' ';
if ((s = va_arg(ap, char *)) == 0)
s = "(null)";
if (precision == 0)
precision = 32767;
for (p = s; *p && (--precision >= 0); p++)
;
break;
case 'D':
case 'd':
case 'I':
case 'i':
if (is_long)
l = va_arg(ap, long);
else
l = va_arg(ap, int);
if (l < 0) {
*p++ = '-';
l = -l;
}
p = ch_ltoa(p, l, 10);
break;
#if CHPRINTF_USE_FLOAT
case 'f':
f = (float) va_arg(ap, double);
if (f < 0) {
*p++ = '-';
f = -f;
}
p = ftoa(p, f, precision);
break;
#endif
case 'X':
case 'x':
c = 16;
goto unsigned_common;
case 'U':
case 'u':
c = 10;
goto unsigned_common;
case 'O':
case 'o':
c = 8;
unsigned_common:
if (is_long)
l = va_arg(ap, unsigned long);
else
l = va_arg(ap, unsigned int);
p = ch_ltoa(p, l, c);
break;
default:
*p++ = c;
break;
}
i = (int)(p - s);
if ((width -= i) < 0)
width = 0;
if (left_align == FALSE)
width = -width;
if (width < 0) {
if (*s == '-' && filler == '0') {
streamPut(chp, (uint8_t)*s++);
n++;
i--;
}
do {
streamPut(chp, (uint8_t)filler);
n++;
} while (++width != 0);
}
while (--i >= 0) {
streamPut(chp, (uint8_t)*s++);
n++;
}
while (width) {
streamPut(chp, (uint8_t)filler);
n++;
width--;
}
}
}
/**
* @brief System formatted output function.
* @details This function implements a minimal @p printf() like functionality
* with output on a @p BaseSequentialStream.
* The general parameters format is: %[-][width|*][.precision|*][l|L]p.
* The following parameter types (p) are supported:
* - <b>x</b> hexadecimal integer.
* - <b>X</b> hexadecimal long.
* - <b>o</b> octal integer.
* - <b>O</b> octal long.
* - <b>d</b> decimal signed integer.
* - <b>D</b> decimal signed long.
* - <b>u</b> decimal unsigned integer.
* - <b>U</b> decimal unsigned long.
* - <b>c</b> character.
* - <b>s</b> string.
* .
*
* @param[in] chp pointer to a @p BaseSequentialStream implementing object
* @param[in] fmt formatting string
*
* @api
*/
int chprintf(BaseSequentialStream *chp, const char *fmt, ...) {
va_list ap;
int formatted_bytes;
va_start(ap, fmt);
formatted_bytes = chvprintf(chp, fmt, ap);
va_end(ap);
return formatted_bytes;
}
/**
* @brief System formatted output function.
* @details This function implements a minimal @p snprintf()-like functionality.
* The general parameters format is: %[-][width|*][.precision|*][l|L]p.
* The following parameter types (p) are supported:
* - <b>x</b> hexadecimal integer.
* - <b>X</b> hexadecimal long.
* - <b>o</b> octal integer.
* - <b>O</b> octal long.
* - <b>d</b> decimal signed integer.
* - <b>D</b> decimal signed long.
* - <b>u</b> decimal unsigned integer.
* - <b>U</b> decimal unsigned long.
* - <b>c</b> character.
* - <b>s</b> string.
* .
* @post @p str is NUL-terminated, unless @p size is 0.
*
* @param[in] str pointer to a buffer
* @param[in] size maximum size of the buffer
* @param[in] fmt formatting string
* @return The number of characters (excluding the
* terminating NUL byte) that would have been
* stored in @p str if there was room.
*
* @api
*/
int chsnprintf(char *str, size_t size, const char *fmt, ...) {
va_list ap;
MemoryStream ms;
BaseSequentialStream *chp;
size_t size_wo_nul;
int retval;
if (size > 0)
size_wo_nul = size - 1;
else
size_wo_nul = 0;
/* Memory stream object to be used as a string writer, reserving one
byte for the final zero.*/
msObjectInit(&ms, (uint8_t *)str, size_wo_nul, 0);
/* Performing the print operation using the common code.*/
chp = (BaseSequentialStream *)(void *)&ms;
va_start(ap, fmt);
retval = chvprintf(chp, fmt, ap);
va_end(ap);
/* Terminate with a zero, unless size==0.*/
if (ms.eos < size)
str[ms.eos] = 0;
/* Return number of bytes that would have been written.*/
return retval;
}
/** @} */
