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

[Jaroslav Kysela <perex@perex.cz>]

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 .

				Jaroslav

> 
> Regards,
> 
> Hans
> 


-- 
Jaroslav Kysela <perex@perex.cz>
Linux Sound Maintainer; ALSA Project; Red Hat, Inc.
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