Initial commit

Signed-off-by: Dylan Aïssi <dylan.aissi@collabora.com>

AT10085_report.md

+---
+title: "T10085 -- Initial PipeWire evaluation on R-Car"
+papersize: a4
+header-includes:
+ - \usepackage{a4wide}
+ - \usepackage{fancyhdr}
+ - \pagestyle{fancy}
+ - >
+  \fancyfoot[C]{\thepage \\
+  Copyright © 2023 Collabora Ltd. }
+linkcolor: blue
+colorlinks: true
+---
+
+[PipeWire](https://pipewire.org/) is *de facto* the new audio server used by all
+major Linux distributions (including Debian and Apertis). It provides a
+low-latency, graph-based processing engine on top of audio and video devices
+that can be used to support the use cases currently handled by both [PulseAudio](https://www.freedesktop.org/wiki/Software/PulseAudio/)
+and [JACK](https://jackaudio.org/).
+
+The goal for this task is to evaluate PipeWire in known problematic use-cases
+with JACK, primarily in supporting multiple audio streams and dynamic switching
+between them between outputs.
+
+
+# Set-up the R-Car board
+To evaluate Pipewire, we will use an [R-Car Starter Kit Premier board](https://elinux.org/R-Car/Boards/H3SK)
+(`RTP8J779M1ASKB0SK0SA003`) with several [Leagy USB Sound Cards](https://www.amazon.de/-/en/External-Speakers-Surround-Simultaneous-Recording/dp/B07VSHCGWD/).
+
+The first step is to install Apertis v2023 (previous Apertis releases don't
+support R-Car audio output) on the board eMMC. Running tests from Apertis
+installed in an SD card is not recommended as it may reduce performance.
+
+The support of R-Car audio output has recently been added to the Apertis v2023
+linux kernel, thus we need at least linux [6.1.20-2~bpo11+1+apertis4](https://gitlab.apertis.org/pkg/linux/-/merge_requests/262).
+
+To avoid having to update the kernel after installing Apertis, we will flash a
+daily image (i.e. built after 2023.10.10) of Apertis which includes the required
+kernel.
+
+The easiet way to achieve that is first to flash Apertis on an SD card, then use
+this SD card to boot the board. From there, we can flash Apertis on the eMMC.
+
+## How to flash Apertis on SD card
+
+First, insert your SD card in a computer then run `fdisk -l` to identify by
+which device it is referenced:
+```
+$ sudo fdisk -l
+
+Disk /dev/mmcblk0: 29.72 GiB, 31914983424 bytes, 62333952 sectors
+Units: sectors of 1 * 512 = 512 bytes
+Sector size (logical/physical): 512 bytes / 512 bytes
+I/O size (minimum/optimal): 512 bytes / 512 bytes
+Disklabel type: gpt
+Disk identifier: XXXXXXXX-XXXX-XXXX-XXXX-XXXXXXXXXXXX
+
+Device           Start     End Sectors   Size Type
+/dev/mmcblk0p1      34  500000  499967 244.1M EFI System
+/dev/mmcblk0p2  500001 5859375 5359375   2.6G Linux filesystem
+/dev/mmcblk0p3 5859376 7812466 1953091 953.7M Linux filesystem
+```
+In our example, SD card is `/dev/mmcblk0`. Now, we can tell bmaptool to copy our
+Apertis image to the SD card:
+```
+$ sudo bmaptool copy https://images.apertis.org/daily/v2023/20231010.0115/arm64/hmi/apertis_v2023-hmi-arm64-uboot_20231010.0115.img.gz /dev/mmcblk0	# FIXME: kernel panic
+$ sudo bmaptool copy https://images.apertis.org/daily/v2023/20231010.0115/arm64/fixedfunction/apertis_v2023-fixedfunction-arm64-uboot_20231010.0115.img.gz /dev/mmcblk0
+```
+Once copying is complete, the SD card is ready to go in our R-car board.
+
+## How to flash Apertis on eMMC
+Before, booting your board, you will have to use a microUSB cable to connect the
+PC to R-Car board and then open a serial console with for instance picocom:
+
+```
+$ sudo dmesg | tail	# To help identifying the tty device name
+$ sudo picocom -b 115200 /dev/ttyUSB0
+```
+
+Now, it's time to boot the board, if u-boot is correctly configured, apertis will
+start otherwise, you will have to re-install a new one (please refer to the
+Apertis documentation to update u-boot, see [rcar-gen3_setup](https://www.apertis.org/reference_hardware/rcar-gen3_setup/#updating-u-boot)).
+
+Once, you have access to the Apertis shell, the first step is to add enable
+`development` repositories by adding
+`deb https://repositories.apertis.org/apertis/ v2023 development` to `/etc/apt/sources.list`
+```
+$ sudo vi /etc/apt/sources.list
+$ sudo apt update && sudo apt install bmap-tools
+```
+Once, `bmap-tools` is installed, you can flash Apertis on the eMMC. Please refer
+to steps above to identify the device name of your eMMC and how to use `bmaptool copy`.
+
+When, Apertis is flashed on the eMMC, it's time to remove the SD card from the
+board and to reboot the board.
+
+## How to check if sound works
+After re-enabling `development` repositories to `sources.list`, we can install
+some tools:
+```
+$ sudo apt update
+$ sudo apt install alsa-utils pulseaudio-utils pipewire
+```
+
+If the linux kernel is recent enough, you should have sound cards registrered:
+```
+$ aplay -l
+**** List of PLAYBACK Hardware Devices ****
+card 0: rcarsound [rcar-sound], device 0: rsnd-dai.0-ak4613-hifi ak4613-hifi-0 []
+  Subdevices: 1/1
+  Subdevice #0: subdevice #0
+card 0: rcarsound [rcar-sound], device 1: rsnd-dai.1-i2s-hifi i2s-hifi-1 []
+  Subdevices: 1/1
+  Subdevice #0: subdevice #0
+```
+
+The tool `speaker-test` can be used to verify if speakers can make sound, but
+before we need to bump the volume of `DVC Out` with:
+```
+alsamixer -D hw:0
+```
+Select the item `DVC Out` with the left and right arrows and then use the up and
+down arrows to adjust the volume. Now, `speaker-test` should make noise (be
+careful when using a headset because the volume can be quite loud).
+
+# Test case 1: Switching audio streams onto running devices
+
+![Test case 1](audio-test-1.png){#id .class width=50% }
+
+FIXME
+
+# Test case 2: Audio input reconfiguration
+
+![Test case 2](audio-test-2.png){#id .class width=50% }
+
+FIXME
+
+# Test case 3: Capturing multiple inputs to multiple outputs
+
+![Test case 3](audio-test-3.png){#id .class width=50% }
+
+FIXME
+
+# Test case 4: Benchmarking load caused by a bigger number of clients
+
+![Test case 4](audio-test-4.png){#id .class width=50% }
+
+FIXME
+
+# Test case 5: xrun behaviour under load
+
+FIXME
+
+# References
+- [T10085: Initial pipewire evaluation on r-car](https://phabricator.apertis.org/T10085)
+- [PipeWire's website](https://pipewire.org/)
+- [Enable R-Car audio output in Apertis v2023-updates](https://gitlab.apertis.org/pkg/linux/-/merge_requests/262)
+- [Enable R-Car audio output in Apertis v2024pre](https://gitlab.apertis.org/pkg/linux/-/merge_requests/264)
+- [R-Car Starter Kit Premier board](https://elinux.org/R-Car/Boards/H3SK)
+- [Leagy USB Sound Card](https://www.amazon.de/-/en/External-Speakers-Surround-Simultaneous-Recording/dp/B07VSHCGWD/)

Makefile

+#!/usr/bin/make -f
+
+all:
+	pandoc -f markdown-implicit_figures AT10085_report.md -o AT10085_report.pdf
+	pandoc AT10085_report.md -o AT10085_report.html