Maxim Levitsky wrote: > Andreas Mohr wrote: >> Hi, >> >> On Wed, Nov 12, 2008 at 07:07:04PM +0200, Maxim Levitsky wrote: >>> I pretty much studied the datasheet and driver, and this is what I >>> found: >>> btw, my acer 5720 and aspire one share same ALC268. >>> Some stuff is trivially fixable, some seems to be unfixable at all: >> >> Wow, what an extremely in-depth analysis! >> I just intended to dive into getting mic routing corrected myself, >> thus you saved me a lot of time! >> >>> model=acer is used on my regular laptop. >>> model-acer-aspire is used on aspire one laptop, and it needs to be >>> renamed, as both are aspire. >> >> +1 (your analysis of both being rather different - as already pondered - >> confirms this necessity) >> >>> And now for unfixable problems: >>> >>> 1) There is strong DC offset on all inputs. >>> it is even different on left/right and depends on capture volume. >>> I tried to change the VREF only param that could help, but it doesn't. >>> I feel that this is hardware flaw. >>> (It is possible that voltage on inputs is created by circuit made by >>> acer, and then ALC268 amplifies it.) >> >> Sounds like really bad circuit design then. >> One would think that the Intel HDA architecture might have builtin >> measures to compensate for this if needed? DC offset issues on >> soundcards aren't exactly a new phenomenon after all... >> >>> Lastly I noticed that datasheet mentions so called 'coefficients': >>> the codecs exposes lots of internal and undocumented registers using >>> set address/ get/set value scheme. >>> maybe some of above bugs are fixable there, but ether realtek has to >>> provide data for that or reverse engineering of >>> windows driver is required. >> >> I've actually had a peek at the .inf files since I thought that it would >> already contain register values in those registry keys that it creates on >> install, but yeah, that's all in-driver it seems. >> Probably time to ask Acer about specifics, especially since I didn't spot >> any hda-intel changes in their linux-2.6.23.9lw source. >> >> Thank you very much, >> >> Andreas Mohr > > Small update: > > 1) The dc offset isn't present on aspire one, really is a circuit design > bug I guess 2) Internal mic works perfectly on aspire one, can reproduce > the strange behaver at all, > Probably this was mixer bug. Finally, I found how to reproduce that bug, I mean to get normal volume on internal mic, I have to increase volume only on left or right channel. So, this happens always, and _only_ when recording _mono_ sound from internal mic. Since hardware doesn't support hardware mono input, tested with -D hw:0 I suspect this to be alsa-lib bug, any ideas? Happens with arecord -D plughw:0 -c1 . Best regards, Maxim Levitsky > > So aspire one support is almost, only need to add support to restore > beep volume > after resume. > > > Best regards, > Maxim Levitsky > > _______________________________________________ Alsa-devel mailing list Alsa-devel@xxxxxxxxxxxxxxxx http://mailman.alsa-project.org/mailman/listinfo/alsa-devel
