Messages in this thread Patch in this message | | | Date | Tue, 24 Aug 2004 19:27:29 +0200 | From | Takashi Iwai <> | Subject | Re: [patch] intel8x0 latency fix |
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At Fri, 20 Aug 2004 18:19:12 +0200, karl.vogel@seagha.com wrote: > > karl.vogel@seagha.com writes: > > > # lspci -s 00:06.0 > > 00:06.0 Multimedia audio controller: nVidia Corporation nForce3 Audio (rev a2) > > > > latency: 50752 us, entries: 267 (267) > > > Following patch fixes it for 2 channel devices (like my notebook). Although I'm > not sure if this is all that useful... if there are workloads other than audio > work that need low latency, then this might be useful. >
In the recent version (linux-sound tree), we can use msleep() (that is more latency friendely) in that callback. The following patch was applied to the current version.
Takashi
--- linux/sound/pci/intel8x0.c 17 Aug 2004 17:09:19 -0000 1.158 +++ linux/sound/pci/intel8x0.c 23 Aug 2004 13:57:52 -0000 @@ -1024,8 +1024,10 @@ /* reset to 2ch once to keep the 6 channel data in alignment, * to start from Front Left always */ - iputdword(chip, ICHREG(GLOB_CNT), (cnt & 0xcfffff)); - mdelay(50); /* grrr... */ + if (cnt & ICH_PCM_246_MASK) { + iputdword(chip, ICHREG(GLOB_CNT), cnt & ~ICH_PCM_246_MASK); + msleep(50); + } } else if (chip->device_type == DEVICE_INTEL_ICH4) { if (sample_bits > 16) cnt |= ICH_PCM_20BIT; - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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