A NOTE has been added to this issue. ====================================================================== <https://bugtrack.alsa-project.org/alsa-bug/view.php?id=2258> ====================================================================== Reported By: Human Assigned To: ====================================================================== Project: ALSA - driver Issue ID: 2258 Category: PCI - intel8x0 Reproducibility: always Severity: major Priority: normal Status: new Distribution: KnoppMyth Kernel Version: 2.6.17-chw-2 ====================================================================== Date Submitted: 07-05-2006 22:12 CEST Last Modified: 07-11-2006 18:54 CEST ====================================================================== Summary: nForce4 + intel8x0 + Dolby Digital 5.1 + S/PDIF = crackle at start of playback Description: Playing stereo audio never causes a crackle. However, playback of 5.1 Dobly Digital content (standalone audio or audio embedded in video) causes a quick but very loud sub-second audio crackle before playback continues, when the previous playback was _not_ also multi-channel content. The problem always happens when the card is being asked to _switch_ to multichannel audio _from_ either stereo or a non-initialized state. The crackle happens on both coaxial and optical S/PDIF connections to the nForce4 (CK804) onboard soundcard. The same receiver has not had a problem with S/PDIF with a different card (Chaintech AV-710 / ice1724). ====================================================================== ---------------------------------------------------------------------- tiwai - 07-11-06 18:38 ---------------------------------------------------------------------- It's a known problem of SPDIF on nForce chipsets. SPDIF non-audio output doesn't work well because of lack of proper SPDIF status bit setting. Since SPDIF is transmitted directly from the audio chip, the changing register in AC97 codec doesn't help. Unfortuantely, we have no datasheet to fix this... ---------------------------------------------------------------------- Human - 07-11-06 18:54 ---------------------------------------------------------------------- Hi, tiwai. I don't understand the cause fully, but maybe I can still help. Is a workaround possible? Half a second of silence would be far better than half a second of static. Perhaps muting the line, then using the buggy procedure, then unmuting? Or is the problem that the receiver is being asked to switch to multichannel mode in such a way that the receiver interprets part of the switch request as audible noise, so muting the source would not help? Is any workaround possible? As for a real fix, has nVidia refused to provide the necessary datasheet for the nForce4 chipset when asked? If you tell me what specifically would help fix the problem, I will do what I can to provide it. I don't exactly have an "in" with nVidia, but as a vendor who sells nVidia products, they have assigned Linux troubleshooting techs to my requests in the past. Finally, if you point me to the relevant code in which the S/PDIF status bit is set, couldn't I iterate through all possible settings and eventually find the right one? If the solution space is small enough, it may be feasible. Are we talking a 4-bit value or a 16-bit value? If it's not appropriate to keep conversing back and forth in this bug report, we can switch to email. Issue History Date Modified Username Field Change ====================================================================== 07-05-06 22:12 Human New Issue 07-05-06 22:12 Human File Added: asound.conf 07-05-06 22:12 Human Distribution => KnoppMyth 07-05-06 22:12 Human Kernel Version => 2.6.17-chw-2 07-05-06 22:13 Human Issue Monitored: Human 07-11-06 18:34 Human Note Added: 0010977 07-11-06 18:38 tiwai Note Added: 0010978 07-11-06 18:54 Human Note Added: 0010979 ====================================================================== ------------------------------------------------------------------------- Using Tomcat but need to do more? Need to support web services, security? Get stuff done quickly with pre-integrated technology to make your job easier Download IBM WebSphere Application Server v.1.0.1 based on Apache Geronimo http://sel.as-us.falkag.net/sel?cmd=lnk&kid=120709&bid=263057&dat=121642 _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.sourceforge.net/lists/listinfo/alsa-devel
