[Bug 1867] New: direct sound (wineoss) records when plays, generating dma overruns

[Wine Bugs]

http://bugs.winehq.com/show_bug.cgi?id=1867

           Summary: direct sound (wineoss) records when plays, generating
                    dma overruns
           Product: Wine
           Version: 20030318
          Platform: All
        OS/Version: Linux
            Status: UNCONFIRMED
          Severity: major
          Priority: P3
         Component: wine-multimedia
        AssignedTo: wine-bugs at winehq.com
        ReportedBy: Jskud at Jskud.com


>From Jskud Sun Dec  7 14:33:12 -0800 2003
From: Jskud at Jskud.com
To: discuss at crossover.codeweavers.com
Subject: mystery solved: why bad/no sound with QuickTimePlayer on CX-plugin 2.0.2
Reply-to: Jskud at Jskud.com

Problem

	crappy sound with (latest) standard i810_audio driver

	no sound with (latest) ALSA intel8x0 driver

Cause

	i810_audio driver enables record and playback triggers on open;
	wineoss respects the current triggers; Intel ICH3 (the /dev/dsp
	controller) will read data on playback.  Since the client is not
	draining the input buffer, there is an overrun, and disruptive
	error handling, with poor real time audio behavior, ensues.

	intel8x0: traced it as far as mmap failure (EIO) in wineoss.

Possible Solutions

	Patch the i810_audio driver to disable PCM_ENABLE_INPUT on open

		#if 0
			dmabuf->trigger |= PCM_ENABLE_INPUT;
		#endif
	
	Hack wineoss to disable the triggers on (device) open, since it
	carefully preserves them thereafter.

	Use better hardware (Intel ICH5 does not exhibit this behavior)

Verification

	Patched the i810_audio driver, and QuickTimePlayer works great.

Details

	I recently purchased and installed Crossover Plugin 2.0.2, and
	installed the WinDoze QuickTime plugin (6.3, per the FAQ --
	thanks).  All this on my Dell Inspiron 4150, using a chipset
	with the Intel ICH3, running RedHat 8.0, with the latest kernel,
	2.4.20-24.8, installed.

	There were no problems playing sound with xmms.  However, I had
	poor sound via QuickTimePlayer with the native i810_audio
	driver, so I installed the latest version of ALSA (1.0.0rc1),
	and configured the intel8x0 driver.  Worse, now I had no sound
	with QuickTimePlayer.

	I enabled debug channels, and discovered that some mmap call in
	wineoss was failing with EIO when using ALSA.  But I also
	noticed I had "dma overrun" messages using the simpler
	(non-ALSA) default i810_audio, and decided to investigate that.

	The Cause and Solution above report my findings.

/Jskud

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