Hi Takashi,
-----Original Message----- From: Takashi Iwai [mailto:tiwai@suse.de] Sent: Monday, March 07, 2016 11:19 PM To: libin.yang@linux.intel.com Cc: alsa-devel@alsa-project.org; Lin, Mengdong; Yang, Libin Subject: Re: [alsa-devel] [RFC PATCH 4/4] ALSA - hda: add DP MST support
On Mon, 07 Mar 2016 15:57:46 +0100, libin.yang@linux.intel.com wrote:
From: Libin Yang libin.yang@linux.intel.com
This patch adds the DP MST support in hdmi audio driver.
sound/pci/hda/hda_codec.c | 3 + sound/pci/hda/patch_hdmi.c | 167
+++++++++++++++++++++++++++++++--------------
2 files changed, 120 insertions(+), 50 deletions(-)
diff --git a/sound/pci/hda/hda_codec.c b/sound/pci/hda/hda_codec.c index 1a42c51..7244f87 100644 --- a/sound/pci/hda/hda_codec.c +++ b/sound/pci/hda/hda_codec.c @@ -589,6 +589,9 @@ static int read_pin_defaults(struct hda_codec
*codec)
pin->nid = nid; pin->cfg = snd_hda_codec_read(codec, nid, 0,AC_VERB_GET_CONFIG_DEFAULT, 0);
/* all device entries are the same widget control so far* fixme: if any codec is different, need fix here*/AC_VERB_GET_PIN_WIDGET_CONTROL,
0);diff --git a/sound/pci/hda/patch_hdmi.c
b/sound/pci/hda/patch_hdmi.c
index 11be04a..26f5efd 100644 --- a/sound/pci/hda/patch_hdmi.c +++ b/sound/pci/hda/patch_hdmi.c @@ -144,7 +144,9 @@ struct hdmi_spec { struct snd_array cvts; /* struct hdmi_spec_per_cvt */ hda_nid_t cvt_nids[4]; /* only for haswell fix */
- int num_pins;
- int num_pins; /* number of pins (including device entries) */
- int num_nids; /* number of pin nids*/
- int dev_num;
These new definitions are unclear to me. Please give a bit more detailed comments there. e.g. what actually means "including device entries"? You can give some example there. I suppose num_nids is the actual number of pins, right? Also what is dev_num? It's not an index, right?
OK. I will add more comments in the code. For this case: 1. num_pins is the virtual pin number. For example, there are 3 pins and each pin has 4 device entry, the num_pins will be 12. 2. num_nids is the actual number of pins. For the above case it will be 3 3. dev_num is the device entry number on each pin. For the above case, it is 4. dev_num is used to decide to create how many pcms (as we talked before, num_nids + dev_num - 1, on Intel platform, it is 5 pcms) For more complex case (not sure there is such case in reality), pin 1 has 2 device entries, pin 2 and pin 3 has 3 device entries. The dev_num is 3. And 5 pcms will be created.
For device entry index, the index is located in per_pin struct.
Regards, Libin
thanks,
Takashi