X-Git-Url: https://git.zerfleddert.de/cgi-bin/gitweb.cgi/m1-debian/blobdiff_plain/b994e9f1d64281464d66ad3b2f7abe8e7e9b7cc0..8adb3bee228c9b16de441033bd26350e18d204e4:/doc/notes.txt

diff --git a/doc/notes.txt b/doc/notes.txt
index 4905a65..af7a0c6 100644
--- a/doc/notes.txt
+++ b/doc/notes.txt
@@ -188,6 +188,9 @@ exec /bin/bash
 
 21:46 < povik> with pulse, you can get the jack by getting into pacmd
 21:46 < povik> and running: load-module module-alsa-sink device=hw:0,1
+21:56 < povik> that mode of playing in parallel through the speakers and jack has a defect
+21:57 < povik> there's noise mixed-in then, at a period
+21:57 < povik> don't know how that happens yet
 
 If you see this in Xorg.0.log, it means that simpledrm has not initialized.
 ...
@@ -211,3 +214,158 @@ CONFIG_BACKLIGHT_GPIO=m
 CONFIG_DRM=y
 CONFIG_DRM_SIMPLEDRM=y
 CONFIG_FB_EFI=n
+
+-------------------------------------------------------------------------------------------------------------
+Howto convert from the old bootchain to the m1n1 chainloaded bootchain:
+
+(air) [~] parted /dev/nvme0n1 print
+Model: APPLE SSD AP0512Q (nvme)
+Disk /dev/nvme0n1: 500GB
+Sector size (logical/physical): 4096B/4096B
+Partition Table: gpt
+Disk Flags:
+
+Number  Start   End    Size    File system  Name                  Flags
+ 1      24.6kB  524MB  524MB                iBootSystemContainer
+ 2      524MB   400GB  399GB                Container
+ 3      400GB   402GB  2501MB
+ 4      402GB   403GB  513MB   fat32                              boot, esp
+ 5      403GB   495GB  91.8GB  ext4         primary
+ 6      495GB   500GB  5369MB               RecoveryOSContainer
+
+I deleted partition 4 and 3, run the asahi installer again.
+
+Than I booted debian from the live stick and mounted the root filesystem and the efi file system:
+
+mount /dev/nvme0n1p5 /mnt
+mount /dev/nvme0n1p4 /mnt/boot/efi
+
+Than I bindmounted the rest of it:
+
+mount -t sysfs none /mnt/sys
+mount -t efivarfs none /mnt/sys/firmware/efi/efivars
+mount -t proc none /mnt/proc
+mount -o bind /dev /mnt/dev
+mount -o bind /dev/pts /mnt/dev/pts
+
+Than I changerooted into it:
+
+cd /mnt
+chroot . bin/bash
+
+blkid
+# Than I updated /etc/fstab with the new id of the efi partition
+
+curl -sLo /boot/efi/m1n1/boot.bin tg.st/u/u-boot.bin
+
+grub-install --removable /boot/efi
+
+exit, umounted everything and rebooted.
+-------------------------------------------------------------------------------------------------------------
+12:41 < chadmed> https://gist.github.com/chadmed/2c772c8fdac8280cb17846388203a213 <- some notes on the speaker system in the j314s, and an asound.conf that makes them sound... okay-ish for now
+
+## BEGIN NOTES ##
+
+# HOUSEKEEPING
+# All testing conducted with channels set to 40% in alsamixer,
+# with no amp gain.
+
+# Do NOT try to play sound with the speakers set to 100% in alsamixer,
+# you will fry the cones!
+
+# DRIVER MAPPINGS/ALSA QUIRKS
+# The speaker array as set up by the ASoC driver maps like
+# this on a J314s:
+# 0: Left Woofer 1
+# 1: Right Woofer 1
+# 2: Left Tweeter
+# 3: Right Tweeter
+# 4: Left (Sub)Woofer 2
+# 5: Right (Sub)Woofer 2
+
+# ALSA sets up the speaker array on the J314s as a 4.0 surround system,
+# with the RL and RR channels duplicated across the woofers like this:
+# 2: Front Left
+# 3: Front Right
+# 0: Rear Left
+# 1: Rear Right
+# 4: Rear Left
+# 5: Rear Right
+
+# Obviously this is not correct, but for us it does not matter, since
+# we can just tell ALSA to route FL and FR to all drivers, presenting
+# it to the rest of userspace as a stereo device. Surround sources
+# are downmixed appropriately.
+
+# SOUND CHECK
+# Testing reveals that drivers 4 and 5 are likely
+# only there to help with bass and sub bass. They
+# are extremely bad at reproducing frequencies above
+# ~500Hz, and even with the help of the tweeters sound
+# rough/deep fried in the mids. Drivers 0 and 1 are obviously
+# intended to be the main woofers in the array.
+
+# If we weren't intending to mimic whatever macOS does, my ear-only
+# testing would have me setting up a xover network like this:
+
+# Freq Range (Hz) | Drivers
+# 0-300 | 0 1 4 5
+# 300-6500 | 0 1
+# 6500-20000 | 2 3
+
+# Figures based on typical {LP,BP,HP}F rolloff characteristics.
+
+# Using all 4 woofers below 300Hz moves more air than just using the
+# (sub)woofers alone. 3-way loudspeakers work like this conventionally.
+
+# The ttable in the j314s-array pcm device tries to compensate for the lack of
+# EQ right now by greatly reducing the volume of 4 and 5, and slightly reducing
+# the volume of 0 and 1 relative to 2 and 3. I have found this gives an acceptably
+# clear sound without being too bright or losing too much out of the mids. Bass is
+# nonexistent, though I suspect this is just because we have not applied appropriate
+# correction to overcome the machine's housing yet. I will not be applying EQ or filtering
+# in ALSA using plugins even in the interim because
+# a) it's deprecated
+# b) it introduces overhead and chews up CPU time
+
+# FIRs can be applied to a 6 channel slave PCM which would then feed the routing table
+# PCM configured below with all coefficients set to 1
+
+## END NOTES ##
+
+# Create a six channel slave for the audio array
+pcm_slave.outputs {
+    pcm "hw:0,0"
+    channels 6
+}
+
+
+# We need to map L and R to the correct drivers. We can use
+# the coefficients in ttable to roughly tune the sound profile.
+pcm.j314s-array {
+    type route
+    slave outputs
+    ttable {
+        0.0 = 0.65
+        0.2 = 1
+        0.4 = 0.3
+        1.1 = 0.65
+        1.3 = 1
+        1.5 = 0.3
+    }
+}
+
+
+# Set up a plug and ctl interface for ALSA defaults
+# XXX: Does not work for PipeWire, but does work for JACK
+# and PulseAudio
+pcm.!default {
+    type plug
+    slave.pcm j314s-array
+}
+
+ctl.!default {
+    type hw
+    card 0
+}
+-------------------------------------------------------------------------------------------------