AC97: Add support for SIS7012 (Fixes #27) #29
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This is based on information from the Linux and FreeBSD AC97/ICH sound drivers, with some local testing and trial'n'error to recover from DMA underruns.
thp
changed the title
| #define ICH_DMABUF_MAX_PERIODS 32 // number of entries in the Buffer Descriptor List | ||
| #define ICH_DMABUF_PERIODS 4 // number of "used" entries in the Buffer Descriptor List | ||
| #define ICH_BDL_ENTRY_SIZE (2 * sizeof(uint32_t)) // size of one entry in the Buffer Descriptor List | ||
| #define ICH_DMABUF_ALIGN (ICH_DMABUF_MAX_PERIODS*ICH_BDL_ENTRY_SIZE) // 256 |
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This is kind of unrelated to SIS7012 support, but during reading of the AC97 docs on OSDev, I found that some of these things look mislabeled (it works because 2 * sizeof(uint32_t) is the same as 2 * 4, even though the "2" doesn't have anything to do with channels. Those values are used for the Buffer Descriptor List.
| size_t buffer_descriptor_list_size = ICH_DMABUF_MAX_PERIODS*ICH_BDL_ENTRY_SIZE; | ||
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| // Allocate Buffer Descriptor List + PCM output buffer in a single allocation | ||
| card->dm = MDma_alloc_cardmem(buffer_descriptor_list_size + card->pcmout_bufsize); | ||
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| // buffer descriptor list requires ICH_BDL_ENTRY_SIZE alignment, | ||
| // but dos-allocmem gives 16 byte align (so we don't need alignment correction) | ||
| card->virtualpagetable = (uint32_t *)card->dm->linearptr; | ||
| card->pcmout_buffer = card->dm->linearptr + buffer_descriptor_list_size; | ||
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| // DMA buffer written by MDma_writedata() and MDma_clearbuf() | ||
| aui->card_DMABUFF = card->pcmout_buffer; |
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Just like above, this is unrelated to SIS7012, but documents this part a little better.
| @@ -322,7 +351,6 @@ static void snd_intel_prepare_playback(struct intel_card_s *card,struct mpxplay_ | |||
| snd_intel_write_32(card,ICH_PO_BDBAR_REG,(uint32_t)pds_cardmem_physicalptr(card->dm,table_base)); | |||
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| snd_intel_write_8(card,ICH_PO_LVI_REG,(ICH_DMABUF_PERIODS-1)); // set last index | |||
| snd_intel_write_8(card,ICH_PO_CIV_REG,0); // reset current index | |||
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The CIV register is read-only in AC97, so I removed writes to it.
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Yeah I saw this too, but I didn't remove it, thought it wouldn't hurt. And yes remove it also wouldn't hurt.
| @@ -598,23 +616,22 @@ static long INTELICH_getbufpos(struct mpxplay_audioout_info_s *aui) | |||
| if(retry>1) | |||
| continue; | |||
| MDma_clearbuf(aui); | |||
| snd_intel_write_8(card,ICH_PO_LVI_REG,(ICH_DMABUF_PERIODS-1)); | |||
| snd_intel_write_8(card,ICH_PO_CIV_REG,0); | |||
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The CIV register is read-only in AC97, so I removed writes to it.
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Is this tested in mpxplay itself? (I guess a backport would be needed for it.) |
Haven't backported it or tested it in MPXPlay. Should be easy to backport, although some |
This is based on information from the Linux and FreeBSD AC97/ICH sound drivers, with some local testing and trial'n'error to recover from DMA underruns.