Hi Takashi, > -----Original Message----- > From: Takashi Iwai [mailto:tiwai@xxxxxxx] > Sent: Monday, March 07, 2016 11:19 PM > To: libin.yang@xxxxxxxxxxxxxxx > Cc: alsa-devel@xxxxxxxxxxxxxxxx; Lin, Mengdong; Yang, Libin > Subject: Re: [RFC PATCH 4/4] ALSA - hda: add DP MST > support > > On Mon, 07 Mar 2016 15:57:46 +0100, > libin.yang@xxxxxxxxxxxxxxx wrote: > > > > From: Libin Yang <libin.yang@xxxxxxxxxxxxxxx> > > > > 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 > > + */ > > pin->ctrl = snd_hda_codec_read(codec, nid, 0, > > > 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 _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
