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| author |   Takashi Iwai <tiwai@suse.de> | 2009-07-16 18:19:12 +0200 |
|---|---|---|
| committer | Takashi Iwai <tiwai@suse.de> | 2010-09-07 11:54:16 +0200 |
| commit | add7c0a6a4b8669ebd726f9c08ba6002900ca671 (patch) | |
| tree | 81c28ffce3985feafc2a6d07f33a7052c763c425 /sound/pci/ca0106 | |
| parent | sound: Remove unnecessary casts of private_data (diff) | |
| download | linux-dev-add7c0a6a4b8669ebd726f9c08ba6002900ca671.tar.xz linux-dev-add7c0a6a4b8669ebd726f9c08ba6002900ca671.zip | |
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: Takashi Iwai <tiwai@suse.de>
Diffstat (limited to 'sound/pci/ca0106')
| -rw-r--r-- | sound/pci/ca0106/ca0106_main.c | 34 |
1 files changed, 16 insertions, 18 deletions
diff --git a/sound/pci/ca0106/ca0106_main.c b/sound/pci/ca0106/ca0106_main.c index 0a3d3d6e77b4..8e69620da20b 100644 --- a/sound/pci/ca0106/ca0106_main.c +++ b/sound/pci/ca0106/ca0106_main.c @@ -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; - 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); - */ - return ptr; + 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; + 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 */ |