Hi,
On 11-12-17 14:40, Takashi Iwai wrote:
On Mon, 11 Dec 2017 13:30:35 +0100,
Hans de Goede wrote:
Hi All,
This weekend I've created a modified ucm config based on:
https://github.com/plbossart/UCM/tree/master/chtrt5645
For a board which has a single speaker connected to the
left channel (standard mono speaker setup) and a stereo
headphone jack with working jack detection.
I've been unable to come up with a ucm file which allows
selecting between a "Stereo Speaker + Headphone" vs
"Mono Speaker + Headphone" output profile.
https://github.com/plbossart/UCM/tree/master/byt-rt5640
has "Mono Speaker", "Stereo Speaker" and "Headphone"
profiles but does not auto-switch between Headphone
and speaker based on jack detection, I've been unable to
allow selecting either stereo or mono speaker while
keeping auto-switching to/from the headphones.
But thinking more about this I don't think that having
"Stereo Speaker + Headphone" and "Mono Speaker + Headphone"
profiles is the answer. Profiles make sense on machines with
a bunch of outputs where we don't no what the user is going
to plug in, but in this case the stereo vs mono speaker
distinction is a clear property of the device, which we
should IMHO autodetect based on the device-model.
So I think we need a way to have different ucm files per board,
so instead of loading /usr/share/ucm/chtrt5645/*.conf on my
device, alsa should try to load /usr/share/ucm/chtrt5645-<boardname>/*.conf
Specifically I'm thinking about using udev + hwdb (dmi string)
matching to set an ALSA_UCM_NAME udev property.
If the consensus is that this is a good idea I can take a shot
at writing patches for this (in my spare time mostly), the
downside of this approach is it would cause a dependency on
libudev for the alsa ucm code.
You don't need to patch, I guess. The recent code should set a string
generated from DMI as the longname of the card, and alsa-lib UCM
parser prefers the longname to the driver name field. That is,
/usr/share/ucm/$LONGNAME/$LONGNAME.conf would be read at first, then
/usr/share/ucm/$DRIVER/$DRIVER.conf is used as fallback.
I'm afraid this does not work entirely as one would expect, after
opening /usr/share/ucm/$LONGNAME/$LONGNAME.conf which contains:
SectionUseCase."HiFi" {
File "HiFi.conf"
Comment "Default"
}
strace shows that alsa-lib opens:
/usr/share/ucm/$DRIVER/HiFi.conf and to get it to load the HiFi.conf
under /usr/share/ucm/$LONGNAME I need to do:
SectionUseCase."HiFi" {
File "../gpd-win-pocket-rt5645/HiFi.conf"
Comment "Default"
}
Leading to the following in strace:
openat(AT_FDCWD, "/usr/share/alsa/ucm/chtrt5645/../gpd-win-pocket-rt5645/HiFi.conF", O_RDONLY) = 23
Which to me seems undesirable behavior by alsa-lib.
Regards,
Hans
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