Messages in this thread Patch in this message | | | Date | Mon, 17 Jan 2005 13:37:08 -0500 | From | "John W. Linville" <> | Subject | [rfc] i810_audio: offset LVI from CIV to avoid stalled start |
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"Some" OSS applications have trouble with later versions of the i810_audio driver. Wolfenstein Enemy Territory from idSoftware is one such application.
I did a little legwork in BK and tracked-down the exact change which caused the break. The changelog comments are dismissive to the original code. However, I find that recreating a patch equivalent to what was removed restores sound to the game.
Anyone have any suggestions for a patch that a) works; and, b) accounts for the concerns expressed in the changelog?
John
P.S. Here is the problematic patch: (DO NOT TRY TO APPLY THIS)
# This is a BitKeeper generated diff -Nru style patch. # # ChangeSet # 2004/05/11 03:51:54-04:00 herbert@gondor.apana.org.au # [sound i810] remove bogus CIV_TO_LVI # # This patch removes a pair of bogus LVI assignments. The explanation in # the comment is wrong because the value of PCIB tells the hardware that # the DMA buffer can be processed even if LVI == CIV. # # Setting LVI to CIV + 1 causes overruns when with short writes # (something that vmware is very fond of). # # drivers/sound/i810_audio.c # 2004/05/11 03:51:52-04:00 herbert@gondor.apana.org.au +0 -10 # [sound i810] remove bogus CIV_TO_LVI # # This patch removes a pair of bogus LVI assignments. The explanation in # the comment is wrong because the value of PCIB tells the hardware that # the DMA buffer can be processed even if LVI == CIV. # # Setting LVI to CIV + 1 causes overruns when with short writes # (something that vmware is very fond of). # diff -Nru a/drivers/sound/i810_audio.c b/drivers/sound/i810_audio.c --- a/drivers/sound/i810_audio.c 2005-01-14 16:20:27 -05:00 +++ b/drivers/sound/i810_audio.c 2005-01-14 16:20:27 -05:00 @@ -1079,25 +1079,15 @@ else port += dmabuf->write_channel->port; - /* if we are currently stopped, then our CIV is actually set to our - * *last* sg segment and we are ready to wrap to the next. However, - * if we set our LVI to the last sg segment, then it won't wrap to - * the next sg segment, it won't even get a start. So, instead, when - * we are stopped, we set both the LVI value and also we increment - * the CIV value to the next sg segment to be played so that when - * we call start_{dac,adc}, things will operate properly - */ if (!dmabuf->enable && dmabuf->ready) { if(rec && dmabuf->count < dmabuf->dmasize && (dmabuf->trigger & PCM_ENABLE_INPUT)) { - CIV_TO_LVI(port, 1); __start_adc(state); while( !(inb(port + OFF_CR) & ((1<<4) | (1<<2))) ) ; } else if (!rec && dmabuf->count && (dmabuf->trigger & PCM_ENABLE_OUTPUT)) { - CIV_TO_LVI(port, 1); __start_dac(state); while( !(inb(port + OFF_CR) & ((1<<4) | (1<<2))) ) ; } -- John W. Linville linville@tuxdriver.com - 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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