[alsa-devel] [PATCH 1/2] ucm: Automatically load the best config file based on the card long name

[Liam Girdwood]

On Wed, 2016-12-21 at 16:12 +0000, Lin, Mengdong wrote:
> > -----Original Message-----
> > From: Liam Girdwood [mailto:liam.r.girdwood at linux.intel.com]
> > Sent: Wednesday, December 21, 2016 10:39 PM
> > 
> > On Wed, 2016-12-21 at 21:09 +0800, mengdong.lin at linux.intel.com wrote:
> > > From: Mengdong Lin <mengdong.lin at linux.intel.com>
> > >
> > > Intel DSP platform drivers are used by many different devices. For
> > > user space to differentiate them, ASoC machine driver may include the
> > > DMI info (vendor, product and board) in card long name. Possible card
> > > long names
> > > are:
> > > broadwell-rt286-Dell Inc.-XPS 13 9343-0310JH
> > 
> > See my previous comments on the kernel patch, but the longname should be
> > like :-
> > 
> > "Dell Inc.-XPS 13"
> 
> May we keep it? It can make the matching code simpler.

Sorry, dont follow. 

> > 
> > > broadwell-rt286-Intel Corp.-Broadwell Client platform-Wilson Beach SDS
> > > bytcr-rt5640-ASUSTeK COMPUTER INC.-T100TA-T100TA
> > > bytcr-rt5651-Circuitco-Minnowboard Max D0 PLATFORM-MinnowBoard
> > MAX ...
> > >
> > > And user space can define configuration files including fields
> > > separated by '.' as below:
> > > broadwell-rt286
> > > broadwell-rt286.Dell.XPS
> > 
> > Dont need to use a . as the names should be unique.
> > 
> > > bytcr-rt5640
> > > bytcr-rt5640.ASUS.T100
> > > bytcr-rt5651.MinnowboardMax
> > > ...
> > >
> > > When being asked to load configuration file of a card, UCM will try to
> > > find the card long name from the local machine, and then scan all
> > > available configuration file names, search every field of config file
> > > name in the card long name. The more characters match, the higher
> > > score the file has. Finally, the file with the highest score will be
> > > loaded to configure the sound card.
> > >
> > > Signed-off-by: Mengdong Lin <mengdong.lin at linux.intel.com>
> > >
> > > diff --git a/src/ucm/parser.c b/src/ucm/parser.c index
> > > c98373a..ff75da7 100644
> > > --- a/src/ucm/parser.c
> > > +++ b/src/ucm/parser.c
> > > @@ -55,6 +55,9 @@ static const char * const component_dir[] = {
> > >  	NULL,		/* terminator */
> > >  };
> > >
> > > +static int filename_filter(const struct dirent *dirent); static int
> > > +is_component_directory(const char *dir);
> > > +
> > >  static int parse_sequence(snd_use_case_mgr_t *uc_mgr,
> > >  			  struct list_head *base,
> > >  			  snd_config_t *cfg);
> > > @@ -1328,6 +1331,210 @@ static int
> > parse_master_file(snd_use_case_mgr_t *uc_mgr, snd_config_t *cfg)
> > >  	return 0;
> > >  }
> > >
> > > +/* trim SPACE (0x20) from the string */ static void trim_space(char
> > > +*str) {
> > > +	int i, j = 0;
> > > +
> > > +	for (i = 0; str[i] && i < MAX_FILE; i++) {
> > > +		if (str[i] != 0x20)
> > > +			str[j++] = str[i];
> > > +	}
> > > +
> > > +	str[j] = '\0';
> > > +}
> > > +
> > > +/* find and store the card long name if the card is in this machine
> > > +*/ static int get_card_long_name(snd_use_case_mgr_t *mgr) {
> > > +	const char *card_name = mgr->card_name;
> > > +	snd_ctl_t *handle;
> > > +	int card, err, dev, idx;
> > > +	snd_ctl_card_info_t *info;
> > > +	const char *_name, *_long_name;
> > > +
> > > +	snd_ctl_card_info_alloca(&info);
> > > +
> > > +	card = -1;
> > > +	if (snd_card_next(&card) < 0 || card < 0) {
> > > +		uc_error("no soundcards found...");
> > > +		return -1;
> > > +	}
> > > +
> > > +	while (card >= 0) {
> > > +		char name[32];
> > > +
> > > +		sprintf(name, "hw:%d", card);
> > > +		err = snd_ctl_open(&handle, name, 0);
> > > +		if (err < 0) {
> > > +			uc_error("control open (%i): %s", card,
> > > +				 snd_strerror(err));
> > > +			goto next_card;
> > > +		}
> > > +
> > > +		err = snd_ctl_card_info(handle, info);
> > > +		if (err < 0) {
> > > +			uc_error("control hardware info (%i): %s", card,
> > > +				 snd_strerror(err));
> > > +			snd_ctl_close(handle);
> > > +			goto next_card;
> > > +		}
> > > +
> > > +		_name = snd_ctl_card_info_get_name(info);
> > > +		if (!strncmp(card_name, _name, 32)) {
> > > +			_long_name = snd_ctl_card_info_get_longname(info);
> > > +			strncpy(mgr->card_long_name, _long_name,
> > > +				MAX_CARD_LONG_NAME);
> > > +			snd_ctl_close(handle);
> > > +			return 0;
> > > +		}
> > > +
> > > +		snd_ctl_close(handle);
> > > +next_card:
> > > +		if (snd_card_next(&card) < 0) {
> > > +			uc_error("snd_card_next");
> > > +			break;
> > > +		}
> > > +	}
> > > +
> > > +	return -1;
> > > +}
> > > +
> > > +/* This function will find the best device-specific configuration
> > > +file based
> > > + * on the sound card long name.
> > > + * Different devices may share the same sound driver and thus the
> > > +same sound
> > > + * card name (short name), but they may still need different
> > > +device-specific
> > > + * configurations. For user space to differentiate them, kernel
> > > +drivers may
> > > + * include the DMI info (vendor, product and board) in the card long
> > name.
> > > + * And user space can define configuration file names appending DMI
> > > +keywords
> > > + * to the card name, like:
> > > + * bytcr-rt5640.ASUS.T100
> > > + * bytcr-rt5651.MinnowBoard
> > > + *
> > > + * When being asked to load the configuration file for a card, this
> > > +function
> > > + * will try to find the card long name from the local machine, and
> > > +then scan
> > > + * all available configuration file names, search every field of the
> > > +config
> > > + * file name in the card long name. The more characters match, the
> > > +higher
> > > + * score the file has. Finally, the file with the highest score will be loaded.
> > > + */
> > 
> > Id' expect this function to try and open card longname and then card name if
> > longname is not found. So providing we use the exact same names as the
> > DMI name we wont need any string formatting or scoring (i.e. file
> > open("longname/longname.conf") will either succeed or fail)
> > 
> > Liam
> 
> I feel we cannot use the exact same names for the configuration file
> and card long name. The DMI info in the card long name can be lengthy,
> including '.' , SPACE, meaningless info like "Corp." and sometime
> duplicated info for some OEMs．I hope developers can just extract key
> words from the messy DMI info to make a simple configuration file
> name, and UCM automatically do the matching and give each
> configuration file a score. Then the file with highest score will be
> used for the card.

Providing the DMI name does not use invalid filename characters we are
ok. Extracting key words and matching is prone to many problems and
painful to debug.... 

The alternative is to include the exact DMI name in a top level config
file that points to the UCM config.

> 
> Thanks
> Mengdong