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Old 12-27-10, 05:07 AM   #1
fluffylob
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Join Date: Nov 2010
Posts: 4
Default Clarification on dmesg output (re HDMI audio)

Hi all,

Apologies if this isn't the right place to post this but it is (I think) a general nvidia / linux question so I thought I'd post it here.

I'm trying to confirm whether or not my system is capable of playing back 24-bit audio and I could use a hand understanding a discrepancy between dmesg output and /proc/asound. I realise my Home Theatre software (XBMC) doesn't yet support 24-bit audio but I'm trying to be ready for when it does - and lend a hand testing the new AudioEngine branch.

My HTPC has a GT210 and is connected via HDMI to an Onkyo TX808 receiver - both sound and video perfectly using XBMC 10.0 on Ubuntu Maverick. I have also tested this on my gaming PC which has a GT460 with the same results.

Put simply, dmesg out put suggests the receiver only supports 16-bit LPCM, whereas the eld file in proc/asound suggests 16,20 and 24-bit. All the documentation for the receiver says it supports 16,20 and 24 - as does Windows 7 if I boot into that. Relevant snippets below.

Can anyone explain to me which of these is more likely to be correct?

Thanks,
Chris

dmesg
Code:
[   37.628058] HDMI: detected monitor TX-NR808
[   37.628062]     at connection type HDMI
[   37.628070] HDMI: available speakers: FL/FR LFE FC RL/RR RLC/RRC
[   37.628080] HDMI: supports coding type LPCM: channels = 2, rates = 44100 48000 88200 176400 192000 384000, bits = 16
[   37.628090] HDMI: supports coding type LPCM: channels = 8, rates = 44100 48000 88200 176400 192000 384000, bits = 16
[   37.628098] HDMI: supports coding type AC-3: channels = 8, rates = 44100 48000 88200, max bitrate = 640000
[   37.628105] HDMI: supports coding type DTS: channels = 8, rates = 48000 88200, max bitrate = 1536000
[   37.628111] HDMI: supports coding type DSD (One Bit Audio): channels = 6, rates = 48000
[   37.628118] HDMI: supports coding type E-AC-3/DD+ (Dolby Digital Plus): channels = 8, rates = 48000 88200
[   37.628126] HDMI: supports coding type DTS-HD: channels = 8, rates = 48000 88200 176400 192000 384000
[   37.628133] HDMI: supports coding type MLP (Dolby TrueHD): channels = 8, rates = 88200 192000
xbmc@xbmc:~$ cat /proc/asound/card0/eld#1.0
Code:
monitor_present         1
eld_valid               1
monitor_name            TX-NR808

connection_type         HDMI
eld_version             [0x2] CEA-861D or below
edid_version            [0x3] CEA-861-B, C or D
manufacture_id          0xcb3d
product_id              0xa82
port_id                 0x20000
support_hdcp            0
support_ai              0
audio_sync_delay        0
speakers                [0x4f] FL/FR LFE FC RL/RR RLC/RRC
sad_count               8
sad0_coding_type        [0x1] LPCM
sad0_channels           2
sad0_rates              [0x1ee0] 44100 48000 88200 176400 192000 384000
sad0_bits               [0xe0000] 16 20 24
sad1_coding_type        [0x1] LPCM
sad1_channels           8
sad1_rates              [0x1ee0] 44100 48000 88200 176400 192000 384000
sad1_bits               [0xe0000] 16 20 24
sad2_coding_type        [0x2] AC-3
sad2_channels           8
sad2_rates              [0xe0] 44100 48000 88200
sad2_max_bitrate        640000
sad3_coding_type        [0x7] DTS
sad3_channels           8
sad3_rates              [0xc0] 48000 88200
sad3_max_bitrate        1536000
sad4_coding_type        [0x9] DSD (One Bit Audio)
sad4_channels           6
sad4_rates              [0x40] 48000
sad5_coding_type        [0xa] E-AC-3/DD+ (Dolby Digital Plus)
sad5_channels           8
sad5_rates              [0xc0] 48000 88200
sad6_coding_type        [0xb] DTS-HD
sad6_channels           8
sad6_rates              [0x1ec0] 48000 88200 176400 192000 384000
sad7_coding_type        [0xc] MLP (Dolby TrueHD)
sad7_channels           8
sad7_rates              [0x1480] 88200 192000
xbmc@xbmc:~$ cat /proc/asound/card0/codec#1
Code:
Codec: Nvidia GT21x HDMI
Address: 1
Function Id: 0x1
Vendor Id: 0x10de000b
Subsystem Id: 0x10de0101
Revision Id: 0x100100
No Modem Function Group found
Default PCM:
    rates [0x0]:
    bits [0x0]:
    formats [0x0]:
Default Amp-In caps: N/A
Default Amp-Out caps: N/A
GPIO: io=0, o=0, i=0, unsolicited=0, wake=0
Node 0x04 [Audio Output] wcaps 0x72b1: 8-Channels Digital Stripe CP
  Control: name="IEC958 Playback Con Mask", index=1, device=0
  Control: name="IEC958 Playback Pro Mask", index=1, device=0
  Control: name="IEC958 Playback Default", index=1, device=0
  Control: name="IEC958 Playback Switch", index=1, device=0
  Device: name="NVIDIA HDMI", type="HDMI", device=7
  Converter: stream=0, channel=0
  Digital:
  Digital category: 0x0
  PCM:
    rates [0x7f0]: 32000 44100 48000 88200 96000 176400 192000
    bits [0xe]: 16 20 24
    formats [0x5]: PCM AC3
  Unsolicited: tag=00, enabled=0
Node 0x05 [Pin Complex] wcaps 0x407381: 8-Channels Digital CP
  Pincap 0x09000094: OUT Detect HBR HDMI DP
  Pin Default 0x18560010: [Jack] Digital Out at Int HDMI
    Conn = Digital, Color = Unknown
    DefAssociation = 0x1, Sequence = 0x0
  Pin-ctls: 0x40: OUT
  Unsolicited: tag=05, enabled=1
  Connection: 1
     0x04
xbmc@xbmc:~$ uname -r
Code:
2.6.35-22-generic
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