Hi Pierre,
On 5/9/2024 6:17 AM, Pierre-Louis Bossart wrote:
On 5/8/24 15:06, Wesley Cheng wrote:
Hi Pierre,
On 5/7/2024 2:40 PM, Pierre-Louis Bossart wrote:
On 5/7/24 14:51, Wesley Cheng wrote:
For userspace to know about certain capabilities of the current platform
card, add tags to the components string that it can use to enable
support
for that audio path. In case of USB offloading, the "usboffldplybk:
1" tag
usboffloadplayback?
same question as before, do we need spaces?
I think spaces are currently used as a delimiter, so I'll remove the
spaces.
And if we have controls, why do we need component strings? The component
string is not dynamic to the best of my knowledge, this could be
problematic if the card is no longer capable of supporting this stream,
while a control can be updated at will.
Maybe I misunderstood your comment here:
https://lore.kernel.org/linux-usb/925d7c03-c288-49a4-8bcd-395b32810d75@xxxxxxxxxxxxxxx/
At the time, I didn't include the kcontrols on the USB SND portion of
it, which was added after this series. My interpretation was that there
were userspace entities that could query for general information about
what the card supports based on the components string, or sound card
name. I treated this as an independent identifier, since the change to
add the offload capable jack was present.
My comment at the time stands: it's very hard to figure out that a
random card supports USB and is connected to a given endpoint.
It'd be much easier as you wrote in the comments on patch 34 to have a
control in the "regular" USB card to point to the 'better' offloaded
path exposed by another card. Applications wouldn't need to know what
this other card is, they would then use the card:device information
directly.
OK, then it might be fine to remove the components tag if patch#34 is
there. That kcontrol is exposed as part of the sound card created for
the USB device, so if applications queried, it would signify that there
is an offload path available.
For this kcontrol, it will return the ASoC platform card index, would
that be sufficient?
Thanks
Wesley Cheng
