diff options
Diffstat (limited to 'Documentation/sound/alsa/DocBook')
| -rw-r--r-- | Documentation/sound/alsa/DocBook/writing-an-alsa-driver.tmpl | 65 |
1 files changed, 39 insertions, 26 deletions
diff --git a/Documentation/sound/alsa/DocBook/writing-an-alsa-driver.tmpl b/Documentation/sound/alsa/DocBook/writing-an-alsa-driver.tmpl index e13c4e67029..87a7c07ab65 100644 --- a/Documentation/sound/alsa/DocBook/writing-an-alsa-driver.tmpl +++ b/Documentation/sound/alsa/DocBook/writing-an-alsa-driver.tmpl @@ -5073,8 +5073,7 @@ struct _snd_pcm_runtime { with <constant>SNDRV_DMA_TYPE_CONTINUOUS</constant> type and the <function>snd_dma_continuous_data(GFP_KERNEL)</function> device pointer, where <constant>GFP_KERNEL</constant> is the kernel allocation flag to - use. For the SBUS, <constant>SNDRV_DMA_TYPE_SBUS</constant> and - <function>snd_dma_sbus_data(sbus_dev)</function> are used instead. + use. For the PCI scatter-gather buffers, use <constant>SNDRV_DMA_TYPE_DEV_SG</constant> with <function>snd_dma_pci_data(pci)</function> @@ -6135,44 +6134,58 @@ struct _snd_pcm_runtime { </para> </section> - <section id="useful-functions-snd-assert"> - <title><function>snd_assert()</function></title> + <section id="useful-functions-snd-bug"> + <title><function>snd_BUG()</function></title> <para> - <function>snd_assert()</function> macro is similar with the - normal <function>assert()</function> macro. For example, + It shows the <computeroutput>BUG?</computeroutput> message and + stack trace as well as <function>snd_BUG_ON</function> at the point. + It's useful to show that a fatal error happens there. + </para> + <para> + 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_assert(pointer != NULL, return -EINVAL); + snd_BUG_ON(!pointer); ]]> </programlisting> </informalexample> - </para> - <para> - The first argument is the expression to evaluate, and the - second argument is the action if it fails. When - <constant>CONFIG_SND_DEBUG</constant>, is set, it will show an - error message such as <computeroutput>BUG? (xxx)</computeroutput> - together with stack trace. - </para> - <para> - When no debug flag is set, this macro is ignored. - </para> - </section> + or it can be used as the condition, + <informalexample> + <programlisting> +<![CDATA[ + if (snd_BUG_ON(non_zero_is_bug)) + return -EINVAL; +]]> + </programlisting> + </informalexample> - <section id="useful-functions-snd-bug"> - <title><function>snd_BUG()</function></title> - <para> - It shows the <computeroutput>BUG?</computeroutput> message and - stack trace as well as <function>snd_assert</function> at the point. - It's useful to show that a fatal error happens there. </para> + <para> - When no debug flag is set, this macro is ignored. + 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> |