> -----Original Message----- > From: Takashi Iwai [mailto:tiwai@xxxxxxx] > Sent: Wednesday, January 13, 2016 7:25 PM > To: libin.yang@xxxxxxxxxxxxxxx > Cc: alsa-devel@xxxxxxxxxxxxxxxx; Lin, Mengdong; Yang, Libin > Subject: Re: [PATCH] ALSA: hda - add DP mst verb support > > On Wed, 13 Jan 2016 12:09:49 +0100, > libin.yang@xxxxxxxxxxxxxxx wrote: > > > > From: Libin Yang <libin.yang@xxxxxxxxxxxxxxx> > > > > Add snd_hda_get_dev_select() and snd_hda_set_dev_select() > functions > > for DP MST audio support. > > > > Signed-off-by: Libin Yang <libin.yang@xxxxxxxxxxxxxxx> > > --- > > sound/pci/hda/hda_codec.c | 54 > +++++++++++++++++++++++++++++++++++++++++++++++ > > sound/pci/hda/hda_codec.h | 2 ++ > > 2 files changed, 56 insertions(+) > > > > diff --git a/sound/pci/hda/hda_codec.c b/sound/pci/hda/hda_codec.c > > index 8374188..95baaba 100644 > > --- a/sound/pci/hda/hda_codec.c > > +++ b/sound/pci/hda/hda_codec.c > > @@ -368,6 +368,60 @@ int snd_hda_get_devices(struct hda_codec > *codec, hda_nid_t nid, > > return devices; > > } > > > > +/** > > + * snd_hda_get_dev_select - get device entry select on the pin > > + * @codec: the HDA codec > > + * @nid: NID of the pin to get device entry select > > + * > > + * Get the devcie entry select on the pin. Return the device entry > > + * id selected on the pin. Return 0 means the first device entry > > + * is selected or MST is not supported. > > + */ > > +int snd_hda_get_dev_select(struct hda_codec *codec, hda_nid_t nid) > > +{ > > + /* not support dp_mst will always return 0, using first dev_entry > */ > > + if (!codec->dp_mst) > > + return 0; > > + > > + return snd_hda_codec_read(codec, nid, 0, > AC_VERB_GET_DEVICE_SEL, 0); > > +} > > +EXPORT_SYMBOL_GPL(snd_hda_get_dev_select); > > + > > +/** > > + * snd_hda_set_dev_select - set device entry select on the pin > > + * @codec: the HDA codec > > + * @nid: NID of the pin to set device entry select > > + * @dev_id: device entry id to be set > > + * > > + * Set the device entry select on the pin nid. > > The return code isn't clearly defined. > > Other than that, it looks OK. What about return dev_id returned from snd_hda_get_dev_select() Or return true if it sets dev_id successfully and false for failure. > But I prefer merging this rather > together with its caller (unless a complex dependency exists). OK. I will submit the patch later. Regards, Libin > > > thanks, > > Takashi > > > + */ > > +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; > > + > > + timeout = jiffies + msecs_to_jiffies(500); > > + > > + /* make sure the device entry selection takes effect */ > > + do { > > + ret = snd_hda_codec_write(codec, nid, 0, > > + AC_VERB_SET_DEVICE_SEL, dev_id); > > + udelay(20); > > + > > + dev = snd_hda_get_dev_select(codec, nid); > > + if (dev == dev_id) > > + break; > > + msleep(20); > > + } while (time_before(jiffies, timeout)); > > + > > + return ret; > > +} > > +EXPORT_SYMBOL_GPL(snd_hda_set_dev_select); > > + > > /* > > * read widget caps for each widget and store in cache > > */ > > diff --git a/sound/pci/hda/hda_codec.h b/sound/pci/hda/hda_codec.h > > index 373fcad..22bcad6 100644 > > --- a/sound/pci/hda/hda_codec.h > > +++ b/sound/pci/hda/hda_codec.h > > @@ -349,6 +349,8 @@ int snd_hda_get_conn_index(struct > hda_codec *codec, hda_nid_t mux, > > hda_nid_t nid, int recursive); > > int snd_hda_get_devices(struct hda_codec *codec, hda_nid_t nid, > > u8 *dev_list, int max_devices); > > +int snd_hda_get_dev_select(struct hda_codec *codec, hda_nid_t nid); > > +int snd_hda_set_dev_select(struct hda_codec *codec, hda_nid_t nid, > int dev_id); > > > > struct hda_verb { > > hda_nid_t nid; > > -- > > 1.9.1 > > _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
