linux-2.6.33/snd_pcm_lib_writev_transfer() の変更点

• 追加された行はこの色です。
• 削除された行はこの色です。
• linux-2.6.33/snd_pcm_lib_writev_transfer() へ行く。
• linux-2.6.33/snd_pcm_lib_writev_transfer() の差分を削除

*参照元 [#p0906ef6]
#backlinks

*説明 [#uecf4553]
-パス: [[linux-2.6.33/sound/core/pcm_lib.c]]

-FIXME: これは何？
--説明


**引数 [#i75451f8]
-struct snd_pcm_substream *substream
--
--[[linux-2.6.33/snd_pcm_substream]]
-unsigned int hwoff
--
-unsigned long data
--
-unsigned int off
--
-snd_pcm_uframes_t frames
--
--[[linux-2.6.33/snd_pcm_uframes_t]]


**返り値 [#rec06036]
-int


**参考 [#j63768f3]


*実装 [#e0b03ce9]
 static int snd_pcm_lib_writev_transfer(struct snd_pcm_substream *substream,
 				       unsigned int hwoff,
 				       unsigned long data, unsigned int off,
 				       snd_pcm_uframes_t frames)
 {
 	struct snd_pcm_runtime *runtime = substream->runtime;
 	int err;
 	void __user **bufs = (void __user **)data;
 	int channels = runtime->channels;
 	int c;
-
--[[linux-2.6.33/snd_pcm_runtime]]

 	if (substream->ops->copy) {
 		if (snd_BUG_ON(!substream->ops->silence))
 			return -EINVAL;
-
--substream->ops は snd_pcm_ops 型のメンバ
--[[linux-2.6.33/snd_pcm_ops]]
-
--[[linux-2.6.33/snd_BUG_ON()]]

 		for (c = 0; c < channels; ++c, ++bufs) {
 			if (*bufs == NULL) {
 				if ((err = substream->ops->silence(substream, c, hwoff, frames)) < 0)
 					return err;
 			} else {
 				char __user *buf = *bufs + samples_to_bytes(runtime, off);
 				if ((err = substream->ops->copy(substream, c, hwoff, buf, frames)) < 0)
 					return err;
 			}
 		}
-
--substream->ops は snd_pcm_ops 型のメンバ
--[[linux-2.6.33/snd_pcm_ops]]

 	} else {
 		/* default transfer behaviour */
 		size_t dma_csize = runtime->dma_bytes / channels;
 		for (c = 0; c < channels; ++c, ++bufs) {
 			char *hwbuf = runtime->dma_area + (c * dma_csize) + samples_to_bytes(runtime, hwoff);
 			if (*bufs == NULL) {
 				snd_pcm_format_set_silence(runtime->format, hwbuf, frames);
 			} else {
 				char __user *buf = *bufs + samples_to_bytes(runtime, off);
 				if (copy_from_user(hwbuf, buf, samples_to_bytes(runtime, frames)))
 					return -EFAULT;
 			}
 		}
-
--[[linux-2.6.33/samples_to_bytes()]]
-
--[[linux-2.6.33/snd_pcm_format_set_silence()]]
-
--[[linux-2.6.33/copy_from_user()]]

 	}
 	return 0;
 }


*コメント [#h0b8c8a8]