Comment 0 for bug 1504227

I am using simultaneously :
- an audio headset connected to the analog audio output,
- a DisplayPort cable to connect my display to my 'AMD Tahiti XT [Radeon HD 7970 ...]' graphics + sound card.

Using the 'Sound' panel of 'gnome-control-center', I systematically get following behaviour for sound output :

- If I choose the 'Line Out - Built-in Audio' device, the sound output comes immediately :
   For example, inside the 'Test Speakers' window, the correct sound systematically starts as soon as I hit any 'Test' button (under 'Front Left' or 'Front Right').

- But if I choose the 'HDMI / DisplayPort - Tahiti XT HDMI Audio [Radeon HD 7970 Series]' device, the sound output starts several seconds LATE :
   For example, inside the 'Test Speakers' window, the sound starts at the end of the 2nd time I hit any 'Test' button (under 'Front Left' or 'Front Right'). Then continuous sound is correct and in sync.
   But after approx. 10s of silence (no sound to output), new sound output starts several seconds LATE again.

$ sudo lspci -nn -vv -s 1:00

01:00.0 VGA compatible controller [0300]: Advanced Micro Devices, Inc. [AMD/ATI] Tahiti XT [Radeon HD 7970/8970 OEM / R9 280X] [1002:6798] (prog-if 00 [VGA controller])
 Subsystem: PC Partner Limited / Sapphire Technology Device [174b:3001]
 Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx+
 Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx-
 Latency: 0, Cache Line Size: 64 bytes
 Interrupt: pin A routed to IRQ 49
 Region 0: Memory at c0000000 (64-bit, prefetchable) [size=256M]
 Region 2: Memory at fea00000 (64-bit, non-prefetchable) [size=256K]
 Region 4: I/O ports at e000 [size=256]
 Expansion ROM at fea40000 [disabled] [size=128K]
 Capabilities: [48] Vendor Specific Information: Len=08 <?>
 Capabilities: [50] Power Management version 3
  Flags: PMEClk- DSI- D1+ D2+ AuxCurrent=0mA PME(D0-,D1+,D2+,D3hot+,D3cold-)
  Status: D0 NoSoftRst- PME-Enable- DSel=0 DScale=0 PME-
 Capabilities: [58] Express (v2) Legacy Endpoint, MSI 00
  DevCap: MaxPayload 256 bytes, PhantFunc 0, Latency L0s <4us, L1 unlimited
   ExtTag+ AttnBtn- AttnInd- PwrInd- RBE+ FLReset-
  DevCtl: Report errors: Correctable- Non-Fatal- Fatal- Unsupported-
   RlxdOrd- ExtTag- PhantFunc- AuxPwr- NoSnoop+
   MaxPayload 128 bytes, MaxReadReq 512 bytes
  DevSta: CorrErr- UncorrErr- FatalErr- UnsuppReq- AuxPwr- TransPend-
  LnkCap: Port #0, Speed 8GT/s, Width x16, ASPM L0s L1, Exit Latency L0s <64ns, L1 <1us
   ClockPM- Surprise- LLActRep- BwNot- ASPMOptComp+
  LnkCtl: ASPM Disabled; RCB 64 bytes Disabled- CommClk+
   ExtSynch- ClockPM- AutWidDis- BWInt- AutBWInt-
  LnkSta: Speed 5GT/s, Width x16, TrErr- Train- SlotClk+ DLActive- BWMgmt- ABWMgmt-
  DevCap2: Completion Timeout: Not Supported, TimeoutDis-, LTR-, OBFF Not Supported
  DevCtl2: Completion Timeout: 50us to 50ms, TimeoutDis-, LTR-, OBFF Disabled
  LnkCtl2: Target Link Speed: 8GT/s, EnterCompliance- SpeedDis-
    Transmit Margin: Normal Operating Range, EnterModifiedCompliance- ComplianceSOS-
    Compliance De-emphasis: -6dB
  LnkSta2: Current De-emphasis Level: -3.5dB, EqualizationComplete-, EqualizationPhase1-
    EqualizationPhase2-, EqualizationPhase3-, LinkEqualizationRequest-
 Capabilities: [a0] MSI: Enable+ Count=1/1 Maskable- 64bit+
  Address: 00000000fee00000 Data: 0000
 Capabilities: [100 v1] Vendor Specific Information: ID=0001 Rev=1 Len=010 <?>
 Capabilities: [150 v2] Advanced Error Reporting
  UESta: DLP- SDES- TLP- FCP- CmpltTO- CmpltAbrt- UnxCmplt- RxOF- MalfTLP- ECRC- UnsupReq- ACSViol-
  UEMsk: DLP- SDES- TLP- FCP- CmpltTO- CmpltAbrt- UnxCmplt- RxOF- MalfTLP- ECRC- UnsupReq- ACSViol-
  UESvrt: DLP+ SDES+ TLP- FCP+ CmpltTO- CmpltAbrt- UnxCmplt- RxOF+ MalfTLP+ ECRC- UnsupReq- ACSViol-
  CESta: RxErr- BadTLP- BadDLLP- Rollover- Timeout- NonFatalErr-
  CEMsk: RxErr- BadTLP- BadDLLP- Rollover- Timeout- NonFatalErr+
  AERCap: First Error Pointer: 00, GenCap+ CGenEn- ChkCap+ ChkEn-
 Capabilities: [200 v1] #15
 Capabilities: [270 v1] #19
 Capabilities: [2b0 v1] Address Translation Service (ATS)
  ATSCap: Invalidate Queue Depth: 00
  ATSCtl: Enable+, Smallest Translation Unit: 00
 Capabilities: [2c0 v1] #13
 Capabilities: [2d0 v1] #1b
 Kernel driver in use: radeon

01:00.1 Audio device [0403]: Advanced Micro Devices, Inc. [AMD/ATI] Tahiti XT HDMI Audio [Radeon HD 7970 Series] [1002:aaa0]
 Subsystem: PC Partner Limited / Sapphire Technology Device [174b:aaa0]
 Control: I/O+ Mem+ BusMaster+ SpecCycle- MemWINV- VGASnoop- ParErr- Stepping- SERR- FastB2B- DisINTx+
 Status: Cap+ 66MHz- UDF- FastB2B- ParErr- DEVSEL=fast >TAbort- <TAbort- <MAbort- >SERR- <PERR- INTx-
 Latency: 0, Cache Line Size: 64 bytes
 Interrupt: pin B routed to IRQ 51
 Region 0: Memory at fea60000 (64-bit, non-prefetchable) [size=16K]
 Capabilities: [48] Vendor Specific Information: Len=08 <?>
 Capabilities: [50] Power Management version 3
  Flags: PMEClk- DSI- D1+ D2+ AuxCurrent=0mA PME(D0-,D1-,D2-,D3hot-,D3cold-)
  Status: D0 NoSoftRst- PME-Enable- DSel=0 DScale=0 PME-
 Capabilities: [58] Express (v2) Legacy Endpoint, MSI 00
  DevCap: MaxPayload 256 bytes, PhantFunc 0, Latency L0s <4us, L1 unlimited
   ExtTag+ AttnBtn- AttnInd- PwrInd- RBE+ FLReset-
  DevCtl: Report errors: Correctable- Non-Fatal- Fatal- Unsupported-
   RlxdOrd- ExtTag- PhantFunc- AuxPwr- NoSnoop+
   MaxPayload 128 bytes, MaxReadReq 512 bytes
  DevSta: CorrErr- UncorrErr- FatalErr- UnsuppReq- AuxPwr- TransPend-
  LnkCap: Port #0, Speed 8GT/s, Width x16, ASPM L0s L1, Exit Latency L0s <64ns, L1 <1us
   ClockPM- Surprise- LLActRep- BwNot- ASPMOptComp+
  LnkCtl: ASPM Disabled; RCB 64 bytes Disabled- CommClk+
   ExtSynch- ClockPM- AutWidDis- BWInt- AutBWInt-
  LnkSta: Speed 5GT/s, Width x16, TrErr- Train- SlotClk+ DLActive- BWMgmt- ABWMgmt-
  DevCap2: Completion Timeout: Not Supported, TimeoutDis-, LTR-, OBFF Not Supported
  DevCtl2: Completion Timeout: 50us to 50ms, TimeoutDis-, LTR-, OBFF Disabled
  LnkSta2: Current De-emphasis Level: -3.5dB, EqualizationComplete-, EqualizationPhase1-
    EqualizationPhase2-, EqualizationPhase3-, LinkEqualizationRequest-
 Capabilities: [a0] MSI: Enable+ Count=1/1 Maskable- 64bit+
  Address: 00000000fee00000 Data: 0000
 Capabilities: [100 v1] Vendor Specific Information: ID=0001 Rev=1 Len=010 <?>
 Capabilities: [150 v2] Advanced Error Reporting
  UESta: DLP- SDES- TLP- FCP- CmpltTO- CmpltAbrt- UnxCmplt- RxOF- MalfTLP- ECRC- UnsupReq- ACSViol-
  UEMsk: DLP- SDES- TLP- FCP- CmpltTO- CmpltAbrt- UnxCmplt- RxOF- MalfTLP- ECRC- UnsupReq- ACSViol-
  UESvrt: DLP+ SDES+ TLP- FCP+ CmpltTO- CmpltAbrt- UnxCmplt- RxOF+ MalfTLP+ ECRC- UnsupReq- ACSViol-
  CESta: RxErr- BadTLP- BadDLLP- Rollover- Timeout- NonFatalErr-
  CEMsk: RxErr- BadTLP- BadDLLP- Rollover- Timeout- NonFatalErr+
  AERCap: First Error Pointer: 00, GenCap+ CGenEn- ChkCap+ ChkEn-
 Kernel driver in use: snd_hda_intel

ProblemType: Bug
DistroRelease: Ubuntu 15.10
Package: linux-image-4.2.0-14-generic 4.2.0-14.16
ProcVersionSignature: Ubuntu 4.2.0-14.16-generic 4.2.2
Uname: Linux 4.2.0-14-generic x86_64
ApportVersion: 2.19-0ubuntu1
Architecture: amd64
AudioDevicesInUse:
 USER PID ACCESS COMMAND
 /dev/snd/pcmC0D0c: z_admin 1665 F...m pulseaudio
 /dev/snd/controlC0: z_admin 1665 F.... pulseaudio
 /dev/snd/controlC1: z_admin 1665 F.... pulseaudio
CurrentDesktop: GNOME
Date: Thu Oct 8 17:46:05 2015
HibernationDevice: RESUME=UUID=ccecc437-66d2-4e39-ac56-76ab11e18140
InstallationDate: Installed on 2015-09-27 (10 days ago)
InstallationMedia: Ubuntu-GNOME 15.10 "Wily Werewolf" - Alpha amd64 (20150924)
IwConfig:
 enp2s0 no wireless extensions.

 lo no wireless extensions.
MachineType: To be filled by O.E.M. To be filled by O.E.M.
ProcFB: 0 radeondrmfb
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.2.0-14-generic root=UUID=a5c156d8-eac3-47fa-835c-b2c4ebda969d ro quiet splash vt.handoff=7
RelatedPackageVersions:
 linux-restricted-modules-4.2.0-14-generic N/A
 linux-backports-modules-4.2.0-14-generic N/A
 linux-firmware 1.149
RfKill:

SourcePackage: linux
UdevLog: Error: [Errno 2] No such file or directory: '/var/log/udev'
UpgradeStatus: No upgrade log present (probably fresh install)
dmi.bios.date: 04/07/2014
dmi.bios.vendor: American Megatrends Inc.
dmi.bios.version: 2501
dmi.board.asset.tag: To be filled by O.E.M.
dmi.board.name: M5A97 R2.0
dmi.board.vendor: ASUSTeK COMPUTER INC.
dmi.board.version: Rev 1.xx
dmi.chassis.asset.tag: To Be Filled By O.E.M.
dmi.chassis.type: 3
dmi.chassis.vendor: To Be Filled By O.E.M.
dmi.chassis.version: To Be Filled By O.E.M.
dmi.modalias: dmi:bvnAmericanMegatrendsInc.:bvr2501:bd04/07/2014:svnTobefilledbyO.E.M.:pnTobefilledbyO.E.M.:pvrTobefilledbyO.E.M.:rvnASUSTeKCOMPUTERINC.:rnM5A97R2.0:rvrRev1.xx:cvnToBeFilledByO.E.M.:ct3:cvrToBeFilledByO.E.M.:
dmi.product.name: To be filled by O.E.M.
dmi.product.version: To be filled by O.E.M.
dmi.sys.vendor: To be filled by O.E.M.