Re: [alsa-devel] [PATCH alsa-lib 1/4] ucm: Fix opening of master-configs by the card's longname

[Hans de Goede <hdegoede@redhat.com>]

Hi,

On 19-11-2019 14:21, Jaroslav Kysela wrote:
> Dne 19. 11. 19 v 13:40 Hans de Goede napsal(a):
>> Hi,
>>
>> On 19-11-2019 13:23, Jaroslav Kysela wrote:
>>> Dne 19. 11. 19 v 11:48 Hans de Goede napsal(a):
>>>> Prior to commit aba2260ae7b5 ("ucm: switch to ucm2 directory and v2 format,
>>>> keep backward compatibility").
>>>>
>>>> The filename build in parse_verb_file() was build like this:
>>>> <prefix>/<uc_mgr->conf_file_name>/<file>
>>>>
>>>> Where uc_mgr->conf_file_name would contain either the card_name or the
>>>> card's longname depending on the detection of a longname based config in
>>>> uc_mgr_import_master_config().
>>>>
>>>> While the filename used in load_master_config() was build like this:
>>>> <prefix>/<card_name>/<card_name>.conf
>>>>
>>>> And uc_mgr_import_master_config() first calls load_master_config()
>>>> with the card's longname and if that succeeds it overwrites
>>>> uc_mgr->conf_file_name with the longname so that the subsequent uses
>>>> of uc_mgr->conf_file_name in parse_verb_file() correctly use the longname.
>>>>
>>>> But the new configuration_filename() helper added in commit aba2260ae7b5
>>>> _always_ builds the filename like this:
>>>> <prefix>/<uc_mgr->conf_file_name>/<file><suffix>
>>>>
>>>> This breaks the loading of the master-config by its longname, as when
>>>> the longname is tried uc_mgr->conf_file_name still contains the card_name.
>>>
>>> Hi Hans,
>>>
>>> This new behaviour was intended for ucm2. I applied all four your patches, and added 10a63e093c4a98acfa9bcdfdd06938bcd874b008 on top which should keep the
>>> new behaviour for v2 configs.
>>
>> Ah I see.
>>
>> There is a bug in the commit you added on top though,
>> when load_master_config() gets called with longname == 1
>> and ALSA_CONFIG_UCM2_VAR is not set and ALSA_CONFIG_UCM_VAR
>> is set, then the if condition in the block is false, so it never executes:
>>
>> +               if (getenv(ALSA_CONFIG_UCM2_VAR) || !getenv(ALSA_CONFIG_UCM_VAR)) {
>> +                       uc_mgr->conf_format = 2;
>> +                       configuration_filename(uc_mgr, filename, sizeof(filename),
>> +                                              uc_mgr->conf_file_name, card_name, ".conf");
>> +               }
>>
>> Causing the next block to also not execute:
>>
>> +               if (uc_mgr->conf_format >= 2 && access(filename, R_OK) != 0) {
>> +                       /* try the old ucm directory */
>> +                       uc_mgr->conf_format = 1;
>> +                       configuration_filename(uc_mgr, filename, sizeof(filename),
>> +                                              card_name, card_name, ".conf");
>> +                       if (access(filename, R_OK) != 0)
>> +                               return -ENOENT;
>> +               }
>>
>> Causing load_master_config() to continue with an uninitialized filename.
>>
>> I think you wanted the following condition for the second block:
>>
>>                   if (uc_mgr->conf_format == 0 || access(filename, R_OK) != 0) {
>>
>> Also don't you want the same behavor wrt forcing the conf_format based
>> on env. when trying the shortname ?
>>
>> I think you can move the entire block under if (longname) to be unconditional,
>> since conf_file_name == card_name for the shortname case using the longname
>> path in the shortname case too is fine. Then you always call configuration_filename
>> with conf_format set and all the handling for conf_format not being set (and
>> for overriding it) can be dropped from configuration_filename() then.
> 
> Thanks again, fixed in 1d848ab739f0d207098627d2ba66421b3ec75eeb .
> 
>>
>>> It's time to create the 1.2.1.1 bugfix alsa-lib release, I guess.
>>
>> Yes that is a good idea (once the above is resolved).
> 
> The tar ball is in ftp://ftp.alsa-project.org/pub/testing .

Thanks, I've given this a quick test spin, the 1.2.1.1 tarbal looks good to me.

Regards,

Hans

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