At Wed, 30 Jul 2008 10:11:32 +0200,
Matthias Dahl wrote:
>
> Hello.
>
> Earlier this month I already posted about my problems with the ALC889a chip.
> I've gathered some more informations that might help or inform others:
>
> 1) the ALC889a is a custom job for Gigabyte and Realtek is not allowed to
> release its data sheet to anyone but Gigabyte. So no data sheet on this
> one.
>
> 2) There seem to be two revisions of this chip. I was unable to confirm this
> with Realtek but my revision id is 0x100101 whereas ALSA expects 0x100103.
>
> Modifing patch_realtek.c appropriately to recognize my revision id and use
> patch_alc883 instead of patch_alc882, doesn't fix the problem but seems to
> help my initial volume problems.
What is this "initial volume problem"?
Could you compare /proc/asound/card0/codec#* outputs between patched
and non-patched cases?
> 3) Sound distortions only appear on the center channel while playing back
> multi channel content. They sound like voltage sizzling noise. Hard to
> explain. Muting all channels but the center channel makes those distortions
> disappear.
Hm, is it via 5.1 channel output with real 6 channels?
The hda-intel driver tries to duplicate 2-channel signals to 5.1
automatically, and it's known that this doesn't always work, e.g. on
AD1986A codec chip. I guess this isn't the case for Realtek codecs,
though.
> A test under Vista revealed no distortions or anything like it. So a faulty
> chip is actually pretty unlikely.
A good news, at least :)
In the recent patch_realtek.c, there are bunch of magical initial
sequences found, e.g. in alc888_coef_init() or in alc_subsystem_id().
Can any of them change the output quality?
alc_fix_pll*() is another magical code, too...
> Since three weeks I am in contact with Realtek about this problem but there is
> not much to report on that front yet except for a rather friendly and helpful
> contact. Unfortunately due to time constraints and other issues, the problem
> hasn't been confirmed nor denied yet by Realtek. They received a similar mb
> from Gigabyte and are planing on trying to reproduce that problem there.
>
> To make a long story short, I'd appreciate if anyone with an ALC889a chip and
> a 5.1 setup could try to confirm this bug and post about it. If anyone knows
> a way how I could diagnose this further, I am open to suggestions...
>
> Currently I tend to get myself an Asus Xonar D2X or similar and keep this as a
> reminder that one should never buy hardware that's not in some way or another
> open. :-( To defend myself, when I bought my board a few weeks back I was
> under the impression that _all_ HDA codecs work well with ALSA and at least
> there I wouldn't have to worry. Well... far from it. :(
HDA codecs are often so delicate. You must care with love :)
Takashi
>
> Thanks a lot in advance for any suggestions or help.
>
> Have a nice day,
> Matthias Dahl
> [2 patch_realtek.c.diff <text/x-diff; us-ascii (7bit)>]
> --- patch_realtek.c.orig 2008-06-27 10:11:58.000000000 +0200
> +++ patch_realtek.c 2008-07-11 11:46:17.000000000 +0200
> @@ -6526,7 +6526,7 @@
> break;
> default:
> /* ALC889A is handled better as ALC888-compatible */
> - if (codec->revision_id == 0x100103) {
> + if (codec->revision_id == 0x100103 || codec->revision_id == 0x100101) {
> alc_free(codec);
> return patch_alc883(codec);
> }
> @@ -14661,8 +14661,10 @@
> { .id = 0x10ec0880, .name = "ALC880", .patch = patch_alc880 },
> { .id = 0x10ec0882, .name = "ALC882", .patch = patch_alc882 },
> { .id = 0x10ec0883, .name = "ALC883", .patch = patch_alc883 },
> - { .id = 0x10ec0885, .rev = 0x100103, .name = "ALC889A",
> + { .id = 0x10ec0885, .rev = 0x100103, .name = "ALC889A rev2",
> .patch = patch_alc882 }, /* should be patch_alc883() in future */
> + { .id = 0x10ec0885, .rev = 0x100101, .name = "ALC889A rev1",
> + .patch = patch_alc883 },
> { .id = 0x10ec0885, .name = "ALC885", .patch = patch_alc882 },
> { .id = 0x10ec0888, .name = "ALC888", .patch = patch_alc883 },
> { .id = 0x10ec0889, .name = "ALC889", .patch = patch_alc883 },
> [3 <text/plain; us-ascii (7bit)>]
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