[11:30] waveform, so digging a bit into the KMS future, i see that v4l2_m2m seems to be pretty well advanced already but i also see that for HW decoding we will need rpivid-v4l2.dtbo loaded, should we not have dtoverlay=rpivid-v4l2 set in sync as soon as we switch from fkms to kms ? [11:38] ogra, probably on desktop (the only platform where kms is currently set), but I'm not sure how/whether it interferes with any of the legacy stuff which still works (to some extent). Another of those "more research needed" bits [11:39] yeah ... i'm starting to play with it ... prob is that you need all userspace apps patched too ... i.e. ffmpeg, kodi, vlc ... [11:39] * ogra hugs snaps ... they make that easier ... [11:41] one other issue i have with KMS is that our pulse snap does not find HDMI devices anymore after switching to kms ... [11:41] i guess there are also some patches needed [11:41] i realize that i can't stay in the past forever though 🙂 [11:41] odd, given that pulse on the desktop image still finds the HDMI devices happily (in fact the audio is less choppy under kms than under fkms there -- it's one of the concerns I have with switching the impish desktop to fkms -- currently testing how bad it gets on different models) [11:42] and yes, the change is painful but it will result in a much more open eco-system for the pi, which can't be a bad thing long-term [11:43] funny, i never have choppy audio in ubuntu core with fkms and pulse from candidate (i do have to hack rthe tsched=0 thingie into it though) [11:43] ah, that's the thing -- with the tsched=0 hack: choppy audio under fkms (and the hack does fix it), but kms is not choppy (on the stock impish desktop) *without* the tsched=0 hack [11:44] definitely ... but i need to give template code to our customers so i need to understand how it works (at least on the surface) [11:44] urgh, I meant *without* the tsched=0 hack -ooops [11:46] well, i see more audio devices in /proc/asound/cards when switching (there seem to be two upstream kernel devices too) but pulse (in the snap) only sees the headphone jack [11:46] hmmm, sounds like a confinement issue [11:47] not sure ... i'll try switching it to devmode for a test ... [11:47] (i wouldnt know why the confinement wouldnt make it find devices it usually has access to ) [11:48] presumably because under kms they're "different devices" to those under fkms (different kernel driver, resulting in a different device? Though ALSA/pulse may label them the same, the underlying path is presumably different) [11:49] right ... i suspect it is more on the alsa level than pulse actually [11:49] with kms enabled i have vc4hdmi and vc4hdmi1 ... and headphones ... pulse doesnt see the vc4hdmi ones [11:54] nope, devmode doesnt seem to change anything ... so not confinement ... [11:55] well, at least the headphone jack works ... (not helpful for TV audio indeed, but pulse itself seems to work) [11:58] i see pulse shipd the whole of /usr/share/alsa in the snap, do we have any special handling in the alsa configs for teh pi that 20.04 didnt have ? [12:00] not that I'm aware of, but alsa is typically desktop team so perhaps they've added some I don't know about? [12:01] i cant imagine that ... [12:01] they dont go out on their own to fiddle with pi stuff i think 🙂 [12:01] not generally, no -- still if it's not confinement it's worth a look [12:02] yeah ... all the bits on UC are 20.04 though ... so any fixes that came in later will not be included yet [12:03] good point [12:05] https://git.alsa-project.org/?p=alsa-lib.git;a=blob;f=src/conf/cards/vc4-hdmi.conf;h=027804a145d1ed9e4fe33dbb5fa7ef278230c328;hb=HEAD [12:05] aha ! [12:05] so there is a special alsa config [12:22] YAY ! [12:22] so re-packing pulse with that file and manually setting the default sink to HDMI works ... [12:23] (now, how do i make it default to HDMI instead of headphones [12:23] ) [12:25] waveform, and you are correct, no tsched hack needed with that [12:26] next stop ... roll an ffmpeg snap with v4l2-m2m support ... [12:26] ah, a special config but upstream -- that makes sense [12:26] * ogra looks at https://github.com/popcornmix/FFmpeg/tree/deinterlace