Commit add7c0a6 authored by Takashi Iwai's avatar Takashi Iwai
Browse files

ALSA: ca0106 - clean up playback pointer callback 



Clean up the playback pointer callback function a bit, and make the
pointer check more strictly to avoid bogus pointers.

Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
parent 9fe856e4

sound/pci/ca0106/ca0106_main.c

+16 −18
Original line number Diff line number Diff line
@@ -1002,29 +1002,27 @@ snd_ca0106_pcm_pointer_playback(struct snd_pcm_substream *substream) 
	struct snd_ca0106 *emu = snd_pcm_substream_chip(substream);

	struct snd_pcm_runtime *runtime = substream->runtime;

	struct snd_ca0106_pcm *epcm = runtime->private_data;

	snd_pcm_uframes_t ptr, ptr1, ptr2,ptr3,ptr4 = 0;

	unsigned int ptr, prev_ptr;

	int channel = epcm->channel_id;

	int timeout = 10;



	if (!epcm->running)

		return 0;



	ptr3 = snd_ca0106_ptr_read(emu, PLAYBACK_LIST_PTR, channel);

	ptr1 = snd_ca0106_ptr_read(emu, PLAYBACK_POINTER, channel);

	ptr4 = snd_ca0106_ptr_read(emu, PLAYBACK_LIST_PTR, channel);

	if (ptr3 != ptr4) ptr1 = snd_ca0106_ptr_read(emu, PLAYBACK_POINTER, channel);

	ptr2 = bytes_to_frames(runtime, ptr1);

	ptr2+= (ptr4 >> 3) * runtime->period_size;

	ptr=ptr2;

	prev_ptr = -1;

	do {

		ptr = snd_ca0106_ptr_read(emu, PLAYBACK_LIST_PTR, channel);

		ptr = (ptr >> 3) * runtime->period_size;

		ptr += bytes_to_frames(runtime,

			snd_ca0106_ptr_read(emu, PLAYBACK_POINTER, channel));

		if (ptr >= runtime->buffer_size)

			ptr -= runtime->buffer_size;

	/*

	printk(KERN_DEBUG "ptr1 = 0x%lx, ptr2=0x%lx, ptr=0x%lx, "

	       "buffer_size = 0x%x, period_size = 0x%x, bits=%d, rate=%d\n",

	       ptr1, ptr2, ptr, (int)runtime->buffer_size,

	       (int)runtime->period_size, (int)runtime->frame_bits,

	       (int)runtime->rate);

	*/

		if (prev_ptr == ptr)

			return ptr;

		prev_ptr = ptr;

	} while (--timeout);

	snd_printk(KERN_WARNING "ca0106: unstable DMA pointer!\n");

	return 0;

}



/* pointer_capture callback */