Re: [alsa-devel] [PATCH 2/4] ALSA: hda - add DP mst verb support

On Mon, 07 Mar 2016 15:57:44 +0100, libin.yang@linux.intel.com wrote:

+int snd_hda_set_dev_select(struct hda_codec *codec, hda_nid_t nid, int dev_id) +{

• int ret, dev;
• unsigned long timeout;
• /* not support dp_mst will always return 0, using first dev_entry */
• if (!codec->dp_mst)

• return 0;
  

• /* If Device List Length is 0, the pin is not multi stream capable.

• */
  

• if ((snd_hda_get_num_devices(codec, nid) + 1) == 0)

• return 0;
  

I don't understand what this code is for. Why +1?

• /* Behavior of setting index being equal to or greater than

• * Device List Length is not predictable
  

• */
  

• if ((snd_hda_get_num_devices(codec, nid) + 1) <= dev_id)

• return 0;
  

Ditto. And, calling the same function twice?

thanks,

Takashi