-----Original Message----- From: Takashi Iwai [mailto:tiwai@suse.de] Sent: Wednesday, December 14, 2016 6:31 PM To: Anand, Jerome jerome.anand@intel.com Cc: intel-gfx@lists.freedesktop.org; alsa-devel@alsa-project.org; ville.syrjala@linux.intel.com; broonie@kernel.org; pierre- louis.bossart@linux.intel.com; Ughreja, Rakesh A rakesh.a.ughreja@intel.com Subject: Re: [PATCH 7/7] ALSA: x86: hdmi: continue playback even when display resolution changes
On Mon, 12 Dec 2016 19:10:43 +0100, Jerome Anand wrote:
When the display resolution changes, the drm disables the display pipes due to which audio rendering stops. At this time, we need to ensure the existing audio pointers and buffers are cleared out so that the playback can restarted once the display pipe is enabled with a different N/CTS values
Signed-off-by: Pierre-Louis Bossart pierre-louis.bossart@linux.intel.com Signed-off-by: Jerome Anand jerome.anand@intel.com
sound/x86/intel_hdmi_audio.c | 21 ++++++++++++++++++--- 1 file changed, 18 insertions(+), 3 deletions(-)
diff --git a/sound/x86/intel_hdmi_audio.c b/sound/x86/intel_hdmi_audio.c index 9249521..d6fd638 100644 --- a/sound/x86/intel_hdmi_audio.c +++ b/sound/x86/intel_hdmi_audio.c @@ -43,6 +43,7 @@ static DEFINE_MUTEX(had_mutex); static int hdmi_card_index = SNDRV_DEFAULT_IDX1; static char *hdmi_card_id = SNDRV_DEFAULT_STR1; static struct snd_intelhad *had_data; +static int underrun_count;
module_param(hdmi_card_index, int, 0444); MODULE_PARM_DESC(hdmi_card_index, @@ -1114,6 +1115,7 @@ static
int
snd_intelhad_open(struct snd_pcm_substream *substream) intelhaddata = snd_pcm_substream_chip(substream); had_stream = intelhaddata->private_data; runtime = substream->runtime;
underrun_count = 0;
pm_runtime_get(intelhaddata->dev);
@@ -1506,10 +1508,23 @@ static snd_pcm_uframes_t snd_intelhad_pcm_pointer(
buf_id = intelhaddata->curr_buf % 4; had_read_register(AUD_BUF_A_LENGTH + (buf_id *
HAD_REG_WIDTH), &t);
- if (t == 0) {
pr_debug("discovered buffer done for buf %d\n", buf_id);/* had_process_buffer_done(intelhaddata); */
- if ((t == 0) || (t == ((u32)-1L))) {
underrun_count++;pr_debug("discovered buffer done for buf %d, count =%d\n",
buf_id, underrun_count);if (underrun_count > (HAD_MIN_PERIODS/2)) {pr_debug("assume audio_codec_reset, underrun =%d - do xrun\n",
underrun_count);underrun_count = 0;return SNDRV_PCM_POS_XRUN;}} else {
/* Reset Counter */underrun_count = 0;}
t = intelhaddata->buf_info[buf_id].buf_size - t;
if (intelhaddata->stream_info.buffer_rendered)
This change itself is OK, but this made me wonder about the driver implementation: the current MAX_PB=1 is the hardware limitation or the soft limitation? That is, can't we play back two streams when we connect two HDMI monitors?
Two streams was never validated from hardware per se. So setting the limitation in software.
thanks,
Takashi