[ALSA] pcm-oss - Add bugg-yptr option

Documentation,ALSA<-OSS emulation
Added 'buggy-ptr' proc option to switch the behavior of GETOPTR ioctl.

Signed-off-by: Takashi Iwai <tiwai@suse.de>

1 files changed, 7 insertions, 1 deletions

diff --git a/sound/core/oss/pcm_oss.c b/sound/core/oss/pcm_oss.c
index 1e606399d74a..a038fd8a53f3 100644
--- a/sound/core/oss/pcm_oss.c
+++ b/sound/core/oss/pcm_oss.c
@@ -1543,7 +1543,11 @@ static int snd_pcm_oss_get_ptr(snd_pcm_oss_file_t *pcm_oss_file, int stream, str
         } else {
                 delay = snd_pcm_oss_bytes(substream, delay);
                 if (stream == SNDRV_PCM_STREAM_PLAYBACK) {
-                        info.blocks = (runtime->oss.buffer_bytes - delay - fixup) / runtime->oss.period_bytes;
+                        snd_pcm_oss_setup_t *setup = substream->oss.setup;
+                        if (setup && setup->buggyptr)
+                                info.blocks = (runtime->oss.buffer_bytes - delay - fixup) / runtime->oss.period_bytes;
+                        else
+                                info.blocks = (delay + fixup) / runtime->oss.period_bytes;
                         info.bytes = (runtime->oss.bytes - delay) & INT_MAX;
                 } else {
                         delay += fixup;
@@ -2350,6 +2354,8 @@ static void snd_pcm_oss_proc_write(snd_info_entry_t *entry,
                                 template.partialfrag = 1;
                         } else if (!strcmp(str, "no-silence")) {
                                 template.nosilence = 1;
+                        } else if (!strcmp(str, "buggy-ptr")) {
+                                template.buggyptr = 1;
                         }
                 } while (*str);
                 if (setup == NULL) {