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author | Mengdong Lin <mengdong.lin@intel.com> | 2013-08-26 21:35:21 -0400 |
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committer | Takashi Iwai <tiwai@suse.de> | 2013-08-27 12:15:09 +0200 |
commit | f1aa06847506d5b88f5eb41fae6a24a7128097e7 (patch) | |
tree | cac7c3bd3fa0cc6a945f2393ab678b263f65b99c /sound/pci/hda/hda_codec.c | |
parent | 68538bf2bce557c3b5fe8c59b034d45352500db1 (diff) | |
download | linux-f1aa06847506d5b88f5eb41fae6a24a7128097e7.tar.bz2 |
ALSA: hda - add flags and routines to get devices selection info for DP1.2 MST
This patch adds flags and routines to get device list & selection info on
a pin.
To support Display Port 1.2 multi-stream transport (MST) over single DP port,
a pin can support multiple devices. Please refer to HD-A spec Document Change
Notificaton HDA040-A.
A display audio codec can set flag "dp_mst" in its patch, indicating its pins
can support MST. But at runtime, a pin may not be multi-streaming capable and
report the device list is empty, depending on Gfx driver configuration.
Signed-off-by: Mengdong Lin <mengdong.lin@intel.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Diffstat (limited to 'sound/pci/hda/hda_codec.c')
-rw-r--r-- | sound/pci/hda/hda_codec.c | 58 |
1 files changed, 58 insertions, 0 deletions
diff --git a/sound/pci/hda/hda_codec.c b/sound/pci/hda/hda_codec.c index fdbb09a9b9e5..5b6c4e3c92ca 100644 --- a/sound/pci/hda/hda_codec.c +++ b/sound/pci/hda/hda_codec.c @@ -666,6 +666,64 @@ int snd_hda_get_conn_index(struct hda_codec *codec, hda_nid_t mux, } EXPORT_SYMBOL_HDA(snd_hda_get_conn_index); + +/* return DEVLIST_LEN parameter of the given widget */ +static unsigned int get_num_devices(struct hda_codec *codec, hda_nid_t nid) +{ + unsigned int wcaps = get_wcaps(codec, nid); + unsigned int parm; + + if (!codec->dp_mst || !(wcaps & AC_WCAP_DIGITAL) || + get_wcaps_type(wcaps) != AC_WID_PIN) + return 0; + + parm = snd_hda_param_read(codec, nid, AC_PAR_DEVLIST_LEN); + if (parm == -1 && codec->bus->rirb_error) + parm = 0; + return parm & AC_DEV_LIST_LEN_MASK; +} + +/** + * snd_hda_get_devices - copy device list without cache + * @codec: the HDA codec + * @nid: NID of the pin to parse + * @dev_list: device list array + * @max_devices: max. number of devices to store + * + * Copy the device list. This info is dynamic and so not cached. + * Currently called only from hda_proc.c, so not exported. + */ +int snd_hda_get_devices(struct hda_codec *codec, hda_nid_t nid, + u8 *dev_list, int max_devices) +{ + unsigned int parm; + int i, dev_len, devices; + + parm = get_num_devices(codec, nid); + if (!parm) /* not multi-stream capable */ + return 0; + + dev_len = parm + 1; + dev_len = dev_len < max_devices ? dev_len : max_devices; + + devices = 0; + while (devices < dev_len) { + parm = snd_hda_codec_read(codec, nid, 0, + AC_VERB_GET_DEVICE_LIST, devices); + if (parm == -1 && codec->bus->rirb_error) + break; + + for (i = 0; i < 8; i++) { + dev_list[devices] = (u8)parm; + parm >>= 4; + devices++; + if (devices >= dev_len) + break; + } + } + return devices; +} + /** * snd_hda_queue_unsol_event - add an unsolicited event to queue * @bus: the BUS |