diff options
| -rw-r--r-- | Documentation/sound/alsa/DocBook/writing-an-alsa-driver.tmpl | 41 | ||||
| -rw-r--r-- | include/sound/core.h | 4 |
2 files changed, 45 insertions, 0 deletions
diff --git a/Documentation/sound/alsa/DocBook/writing-an-alsa-driver.tmpl b/Documentation/sound/alsa/DocBook/writing-an-alsa-driver.tmpl index e13c4e67029f..df699e4323ef 100644 --- a/Documentation/sound/alsa/DocBook/writing-an-alsa-driver.tmpl +++ b/Documentation/sound/alsa/DocBook/writing-an-alsa-driver.tmpl @@ -6173,6 +6173,47 @@ struct _snd_pcm_runtime { When no debug flag is set, this macro is ignored. </para> </section> + + <section id="useful-functions-snd-bug-on"> + <title><function>snd_BUG_ON()</function></title> + <para> + <function>snd_BUG_ON()</function> macro is similar with + <function>WARN_ON()</function> macro. For example, + + <informalexample> + <programlisting> +<![CDATA[ + snd_BUG_ON(!pointer); +]]> + </programlisting> + </informalexample> + + or it can be used as the condition, + <informalexample> + <programlisting> +<![CDATA[ + if (snd_BUG_ON(non_zero_is_bug)) + return -EINVAL; +]]> + </programlisting> + </informalexample> + + </para> + + <para> + The macro takes an conditional expression to evaluate. + When <constant>CONFIG_SND_DEBUG</constant>, is set, the + expression is actually evaluated. If it's non-zero, it shows + the warning message such as + <computeroutput>BUG? (xxx)</computeroutput> + normally followed by stack trace. It returns the evaluated + value. + When no <constant>CONFIG_SND_DEBUG</constant> is set, this + macro always returns zero. + </para> + + </section> + </chapter> diff --git a/include/sound/core.h b/include/sound/core.h index 1a4ff0bdcf6a..938c36a0e874 100644 --- a/include/sound/core.h +++ b/include/sound/core.h @@ -28,6 +28,7 @@ #include <linux/rwsem.h> /* struct rw_semaphore */ #include <linux/pm.h> /* pm_message_t */ #include <linux/device.h> +#include <linux/stringify.h> /* number of supported soundcards */ #ifdef CONFIG_SND_DYNAMIC_MINORS @@ -405,11 +406,14 @@ void snd_verbose_printd(const char *file, int line, const char *format, ...) dump_stack(); \ } while (0) +#define snd_BUG_ON(cond) WARN((cond), "BUG? (%s)\n", __stringify(cond)) + #else /* !CONFIG_SND_DEBUG */ #define snd_printd(fmt, args...) /* nothing */ #define snd_assert(expr, args...) (void)(expr) #define snd_BUG() /* nothing */ +#define snd_BUG_ON(cond) ({/*(void)(cond);*/ 0;}) /* always false */ #endif /* CONFIG_SND_DEBUG */ |