On Wed, 21 Feb 2018 20:02:38 +0100, Pierre-Louis Bossart wrote:

On 2/21/18 9:53 AM, Takashi Iwai wrote:

...

The recent support for the multiple PCM devices allowed user to use multiple HDMI/DP outputs, but at the same time, the PCM stream assignment has been changed, too. Due to that, the former PCM#0 (there was only one stream in the past) is likely assigned to a different one (e.g. PCM#2), and it ends up with the regression when user sticks with the fixed configuration using the device#0.

Although the multiple monitor support shouldn't matter when user deploys the backend like PulseAudio that checks the jack detection state, the behavior change isn't always acceptable for some users.

As a mitigation, this patch introduces an option to switch the behavior back to the old-good-days: when the new option, single_port=1, is passed, the driver creates only a single PCM device, and it's assigned to the first connected one, like the earlier versions did. The option is turned off as default still to support the multiple monitors.

Sounds ok, but would it makes sense to instead of a scalar single-port argument use a look-up table with more values, e.g. with an argument of (2,0,1), the port 0 would be PCM2, port 1 PCM0 and port 2 PCM1?

We can do that, too, but you don't know the mapping unless you really plug, so it's a higher hurdle for users, I'm afraid. Since most of CHV/BYT devices are with a single output, this option is much easier to deal with.

thanks,

Takashi

...

Fixes: 8a2d6ae1f737 ("ALSA: x86: Register multiple PCM devices for the LPE audio card") Reported-and-tested-by: Hubert Mantel mantel@metadox.de Signed-off-by: Takashi Iwai tiwai@suse.de

---

sound/x86/intel_hdmi_audio.c | 14 +++++++++++--- 1 file changed, 11 insertions(+), 3 deletions(-)

diff --git a/sound/x86/intel_hdmi_audio.c b/sound/x86/intel_hdmi_audio.c index a0951505c7f5..96115c401292 100644 --- a/sound/x86/intel_hdmi_audio.c +++ b/sound/x86/intel_hdmi_audio.c @@ -50,6 +50,7 @@ /*standard module options for ALSA. This module supports only one card*/ static int hdmi_card_index = SNDRV_DEFAULT_IDX1; static char *hdmi_card_id = SNDRV_DEFAULT_STR1; +static bool single_port; module_param_named(index, hdmi_card_index, int, 0444); MODULE_PARM_DESC(index, @@ -57,6 +58,9 @@ MODULE_PARM_DESC(index, module_param_named(id, hdmi_card_id, charp, 0444); MODULE_PARM_DESC(id, "ID string for INTEL Intel HDMI Audio controller."); +module_param(single_port, bool, 0444); +MODULE_PARM_DESC(single_port,

• "Single-port mode (for compatibility)");
  

  /*
  • ELD SA bits in the CEA Speaker Allocation data block

@@ -1579,7 +1583,11 @@ static irqreturn_t display_pipe_interrupt_handler(int irq, void *dev_id) static void notify_audio_lpe(struct platform_device *pdev, int port) { struct snd_intelhad_card *card_ctx = platform_get_drvdata(pdev);

• struct snd_intelhad *ctx = &card_ctx->pcm_ctx[port];

• struct snd_intelhad *ctx;
• ctx = &card_ctx->pcm_ctx[single_port ? 0 : port];
• if (single_port)

• ctx->port = port;
  schedule_work(&ctx->hdmi_audio_wq);
  

  }

@@ -1816,7 +1824,7 @@ static int hdmi_lpe_audio_probe(struct platform_device *pdev) init_channel_allocations(); card_ctx->num_pipes = pdata->num_pipes;

• card_ctx->num_ports = pdata->num_ports;

• card_ctx->num_ports = single_port ? 1 : pdata->num_ports; for_each_port(card_ctx, port) { struct snd_intelhad *ctx = &card_ctx->pcm_ctx[port];

@@ -1824,7 +1832,7 @@ static int hdmi_lpe_audio_probe(struct platform_device *pdev) ctx->card_ctx = card_ctx; ctx->dev = card_ctx->dev;

• ctx->port = port;
  

• ctx->port = single_port ? -1 : port;
  

  ctx->pipe = -1; INIT_WORK(&ctx->hdmi_audio_wq, had_audio_wq);