[ubuntu-uk] The tablet everyone is talking about..

[Simos Xenitellis]

On Thu, Apr 8, 2010 at 9:50 PM, Daniel Case <danielcase10 at googlemail.com> wrote:
> I have fixed the problem with the help of some guys in #mer
>
> Sound, does not work out of the box but will work once the last line has
> been removed from /etc/modprobe.d/alsa-base.conf
>
> However in order to fix the crackling you must plug the USB stick into a
> host computer, and change the name of
> /etc/lib/KERNALVERSION/kernal/drivers/acpi/processor.ko on the second
> partition.
>
> I have added it to the wiki and the Etherpad :)
>
> On Thu, Apr 8, 2010 at 6:18 PM, Daniel Case <danielcase10 at googlemail.com>
> wrote:
>>
>> I managed to obtain a new USB stick and run the ALSA tester, i uploaded
>> the results to my new wiki page:
>>
>> http://www.jogglerwiki.info/index.php?title=Alsa
>>
>> On Thu, Apr 8, 2010 at 4:21 PM, Thomas Ibbotson
>> <thomas.ibbotson at gmail.com> wrote:
>>>
>>> On 8 April 2010 16:12, Dan Fish <danfish at nhs.net> wrote:
>>> > I got UNR 9.10 working OK last night.
>>> >
>>> > http://www.ossmedicine.org/joggler1.jpg
>>> >
>>>
>>> That "screenshot" alone has now made me want one, but I really can't
>>> justify getting one, even though it's only £50. It is my birthday on
>>> Saturday, but I've already ordered myself a new computer and all my
>>> family presents have been bought :(
>>>
>>> Tom
>>>

Thanks!

Looking through the alsa-info output, we see that the Sigmatel
STAC9202 chip is being used, with Vendor Id: 0x83847632. The dmesg
output does not show something significant.

Looking at the source code of the Linux kernel and the sound subsystem
(Alsa), we notice:

2c11f955 (Tobin Davis               2007-05-17 09:36:34 +0200 5095)
 case 0x83847632: /* STAC9202  */
2c11f955 (Tobin Davis               2007-05-17 09:36:34 +0200 5096)
 case 0x83847633: /* STAC9202D */
2c11f955 (Tobin Davis               2007-05-17 09:36:34 +0200 5097)
 case 0x83847636: /* STAC9251  */
2c11f955 (Tobin Davis               2007-05-17 09:36:34 +0200 5098)
 case 0x83847637: /* STAC9251D */
f6e9852a (Takashi Iwai              2007-10-16 14:27:04 +0200 5099)
         spec->num_dmics = STAC925X_NUM_DMICS;
2c11f955 (Tobin Davis               2007-05-17 09:36:34 +0200 5100)
         spec->dmic_nids = stac925x_dmic_nids;
1697055e (Takashi Iwai              2007-12-18 18:05:52 +0100 5101)
         spec->num_dmuxes = ARRAY_SIZE(stac925x_dmux_nids);
1697055e (Takashi Iwai              2007-12-18 18:05:52 +0100 5102)
         spec->dmux_nids = stac925x_dmux_nids;
2c11f955 (Tobin Davis               2007-05-17 09:36:34 +0200 5103)
         break;

8e21c34c (Tobin Davis               2007-01-08 11:04:17 +0100 6225)
 { .id = 0x83847632, .name = "STAC9202",  .patch = patch_stac925x },

which means that the 'quirk' code for this specific chipset was added
in 2007 and did not change since. Thus, there might be something in
this newer chipset that needs an update in Alsa.

You mention that you need to remove the 'last' line in alsa-base.conf.
Is it this line?
   # Power down HDA controllers after 10 idle seconds
   options snd-hda-intel power_save=10 power_save_controller=N

If so, then the driver is not able to wake up properly from the power
saving state.

So, what if you want to give back to the Linux community :-), you may
1. Get a full alsa-info.sh output in a text file (the one at the wiki
does not have the first lines, which include the alsa driver version,
etc).
2. Send an e-mail to the alsa-devel mailing list at
http://www.alsa-project.org/main/index.php/Mailing-lists
saying something like

===============
Hi All,
I have an O2 Joggler with the alsa-info output file attached in this message.
The sound does not work unless I remove the following line from
/etc/modprobe.d/alsa-base.conf

    # Power down HDA controllers after 10 idle seconds
    options snd-hda-intel power_save=10 power_save_controller=N

I believe this means that the chipset is not able to wake up from
power saving, and what I get is crackling sound.

What can be done so that this issue is fixed (the device works with
power saving)?

The device came with a special version of Ubuntu Linux 8.04, and the
source code (included Alsa) is available at
http://lists.gpl-violations.org/pipermail/legal/2009-December/001755.html

Thanks!
================

Since you are doing a big investment in this device, it's good to push
it further and get it to work out of the box in newer versions of
Linux.

Simos

-- 
A. Because it breaks the logical sequence of discussion
Q. Why is top posting bad?