From mboxrd@z Thu Jan 1 00:00:00 1970 From: Richard Lemon Subject: possible intel8x0 problem with nforce chip-set Date: 21 Oct 2003 13:18:39 +0930 Sender: alsa-devel-admin@lists.sourceforge.net Message-ID: <1066708119.13971.10.camel@baked.spud.com> Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Return-path: Errors-To: alsa-devel-admin@lists.sourceforge.net List-Help: List-Post: List-Subscribe: , List-Unsubscribe: , List-Archive: To: alsa-devel@lists.sourceforge.net List-Id: alsa-devel@alsa-project.org Hi Guys, I have been using the alsa api for a while working on some multimedia stuff. I believe I have found a bug with the intel8x0 driver when running the nforce chip-set. The problem appears to be an uninitialized variable type problem. The first time you call snd_pcm_mmap_begin() the channels are returned in their pairs in a random order. That is the rear channels may end up in the front or Center/LFE slots, etc, the channel order does not change from then on. I compiled up the pcm.c test code and tried that out. This shows the problem, only worse. If you change the generate_sine function to the following to pick out one pair of channels only. if ((chn == 2) || (chn == 3)) *samples[chn] = ires; else *samples[chn] = 0; then call pcm with the following... ./pcm -r 48000 -c 6 -m direct_noninterleaved I would expect silence from all but the rear pair. What we get is a sequencing of the audio through the 6 channels. It makes no difference which of the modes or rates I use. Am I just misusing the api or is this a bug? Here are the hardware specs. ShuttleX pc North bridge-Nvidia nForce2, South bridge-nVidia MCP-T Realtek ALC650 6 Ch, Support Digital SPDIF Output for more details on hardware. http://www.us.shuttle.com/specs_access.asp?pro_id=284 running Mandrake Linux 9.0. I have tested several of the alsa releases and am currently using 0.9.6. Richard Lemon. ------------------------------------------------------- This SF.net email is sponsored by OSDN developer relations Here's your chance to show off your extensive product knowledge We want to know what you know. Tell us and you have a chance to win $100 http://www.zoomerang.com/survey.zgi?HRPT1X3RYQNC5V4MLNSV3E54