Red Hat Bugzilla – Bug 29562
noise in the sound output on YMF PCI 754 on Toshiba 2805
Last modified: 2007-04-18 12:31:46 EDT
From Bugzilla Helper: User-Agent: Mozilla/4.76 [en] (WinNT; U) The sound is not autodetected by the installer. If I modprobe ymfpci I get a noise in the speakers. rmmod ymfpci reduces the noise but it's still there. The noise is affected only by master volume and pcm volume. Reproducible: Always Steps to Reproduce: 1. modprobe ymfpci 2. 3. Actual Results: Noise in the speakers. The music can barely be heard. Expected Results: Clear sound. Using the ymfpci module from the alsa package fixed the problem. I have used alsa-0.9.0beta.
Assigning to kernel.
I worked with Florin before, he is willing to test patches. However, I am running out of ideas. We know that it is not a chip's internal loopback, and it seems that it is not the legacy block. So, the native PCI block produces these noises. The bug is easy to reproduce on Toshibas, for example Jacob Berkman from Ximian and Jeff Garzik hit it too. If _anyone_ has a failing Toshiba with YMF in Bay Area and is willing to help, please contact me. My home VAIO works just fine, of course... The current plan is to see what the latest ALSA may offer. -- Pete
Tried ALSA's diffs, fixed a bug with microcode loading, but still buzzes! What an evil lot. I think I will not be able to fix this for the release date. Sorry.
Created attachment 15789 [details] Kill volume of P44Slot
I talked to several people, including Nick Brown @coe.int, Jeff Garzik, and others. We figured that the buzzing is produced by the P44Slot on "-E" microcode (it reports non-zero work area size). The easy fix is to mute the P44Slot channel, per attachement. I am concerned by our discovery, because 1. Firmware expends resources to create the buzzing, perhaps affecting other channels. 2. In all probability, the chip hits work area all the time and eats PCI bandwidth 3. There is something about it that we do not understand.