Ouya (ouya-ouya)

== Users owning this device ==
== Safe Boot ==
We avoid flashing the boot partition because a corrupted kernel would irreversibly brick the Ouya. We use a tool called Ouya BootMenu (source) that allows us to chain load the postmarketOS kernel using kexec.
== Audio ==
There are two mechanisms to output audio through HDMI.
* Tegra30 HDA
* Tegra30 SPDIF
The HDA device is what is used by the downstream kernel and stock Ouya Android ROM. The SPDIF device only outputs to the left channel. 
Audio output through the HDA device works on the downstream kernel. The HDA device is card 0 device 3. It can be tested by running speaker-test -Dhw:0,3 -c 2. The SPDIF device is card 1 device 0. It can be tested by running speaker-test -Dhw:1,0 -c 2. 
The mainline kernel has a tegra30-hda driver but it isn't working on Ouya. There is no upstreamed driver for the Tegra30 SPDIF device. 
The Tegra30 HDA driver writes 4 frames and then hangs. 
$ speaker-test -Dhw:0,3 -c 2
speaker-test 1.1.8
Playback device is hw:0,3
Stream parameters are 48000Hz, S16_LE, 2 channels
Using 16 octaves of pink noise
Rate set to 48000Hz (requested 48000Hz)
Buffer size range from 64 to 16384
Period size range from 32 to 8192
Using max buffer size 16384
Periods = 4
was set period_size = 4096
was set buffer_size = 16384
 0 - Front Left
snd_pcm_hw_writei
hw_writei: frames = 4096, xferi.result = 4096, err = 0
snd_pcm_hw_writei
hw_writei: frames = 4096, xferi.result = 4096, err = 0
snd_pcm_hw_writei
hw_writei: frames = 4096, xferi.result = 4096, err = 0
snd_pcm_hw_writei
hw_writei: frames = 4096, xferi.result = 4096, err = 0
snd_pcm_hw_writei
hw_writei: frames = 4096, xferi.result = -5, err = -5
Write error: -5,I/O error
xrun_recovery failed: -5,I/O error
Transfer failed: I/O error
The kernel PCM framework in sound/core/pcm_native.c has a timeout waiting for the device to respond.
[ 691.115717] tegra-hda 70030000.hda: playback write error (DMA or IRQ trouble?)
It is uncertain why the HDA device isn't working on mainline. 
Possible avenues to explore: 
* Compare pinmuxes to downstream kernel.
* Are the necessary clocks enabled and at the correct frequency?
== Ethernet ==
A random MAC address is generated by the kernel at each boot. This is because the smsc9500 Ethernet device does not have a valid mac address stored in EEPROM. To set a consistent MAC address, create the file /etc/udev/rules.d/99-mac-address.rules with the following udev rule. 
ACTION=="add", SUBSYSTEM=="net", KERNEL=="eth0", RUN+="/sbin/ip link set dev %k address f6:23:f0:42:98:cf"
== Radio ==
* The Ouya uses a BCM4330 radio chip for wifi and bluetooth. The downstream and mainline kernel use the same wifi firmware. The firmware shipped with the device is the only known firmware to work with the Ouya. The BCM4330 firmware in linux-firmware does not work. 
* Two later releases (the completely white special edition and completely black 2nd generation) allegedly use a BCM4334 chipset. This needs to be implemented and tested at a future date.
== Display Resolution ==
On the mainline kernel, display resolutions above 1280x720 are glitchy. The GPU is dependent on memory bandwidth but EMC scaling is not implemented in mainline. The Ouya bootloader sets the memory to 400 Mhz. Higher display resolutions work a bit better when the memory is set to 800Mhz but it is still glitchy.
A kernel patchset was committed on 2021-08-13 to add support for memory bandwidth management. This should be released in v5.15.
== HDMI CEC ==
The Ouya is missing HDMI CEC support at the hardware design level. 
References: 
* What remote controls do you want supported? 
* https://forum.kodi.tv/showthread.php?tid=186121
== Other Notes ==
* Splash screen doesn't appear
* USB booting needs to be tested
== Installation ==
=== How to enter flash mode ===
1. Connect Ouya to PC
2. Use adb reboot recovery to enter recovery (or adb reboot bootloader to enter bootloader for fastboot commands)
=== Downloads ===
You'll need OneClickOuyaRecovery.zip from here (original link is dead)
===pmbootstrap===
1. Flash CWM and Ouya BootMenu.
2. Turn on Ouya, then press the power button many times until it scrolls to Bootloader, and then wait until the boot menu disappears.
3. Run the following using pmbootstrap:
$ # You will be asked for the Postmarket Version and Device. Select edge and ouya (with codename ouya).
$ # You may then select the mainline kernel, or the default 3.1 Ouya kernel for installation.
$ pmbootstrap init
$ pmbootstrap install
$ pmbootstrap export
$ # make sure the Ouya is in the bootloader at this point
$ # if this fails, read below (Flashing to the data partition)
$ pmbootstrap flasher flash_rootfs
4. Reboot Ouya, then press the power button many times until it scrolls to Recovery, and then wait until CWM appears.
6. Using CWM menu options, mount /data partition.
7. Copy postmarketOS boot.img to /sdcard as altboot.img:
$ adb push /tmp/postmarketOS-export/boot.img-ouya-ouya /sdcard/altboot.img
8. Reboot Ouya, then press the power button many times until it scrolls to Alternate Boot, and then wait until postmarketOS appears.
=== Using data partition as rootfs ===
It is much more usable to flash rootfs to the data partition which is around 5.7GB in size. 
==== Flashing to the data partition ====
Specify the partition to flash rootfs to with the --partition argument:
$ pmbootstrap flasher flash_rootfs --partition userdata
Boot the Ouya into Recovery and make sure to mount /system in recovery. Copy postmarketOS boot.img and initramfs-extra to /system. Unmount /system.
$ adb push /tmp/postmarketOS-export/boot.img /system/
$ adb push /tmp/postmarketOS-export/initramfs-extra /system/
Do note, if the rootfs is larger than ~750mb Ouya's fastboot won't be able to flash it. In that case you may need to use dd to install the image from a usb drive. This can be done with adb shell in recovery. After you've ran pmbootstrap export ouya-ouya.img will be in /tmp/postmarketOS-export/. Make sure to copy the actual files and not the links in /tmp/postmarketOS-export/.
Boot to recovery, then log into your Ouya with adb shell
# # blkid should list your USB drive as /dev/sda1
# mkdir /tmp/mnt
# mount /dev/sda1 /tmp/mnt
# cd /tmp/mnt
# dd if=ouya-ouya.img of=/dev/block/mmcblk0p9
=== Updating the kernel ===
When the apk package manager updates the kernel package (e.g. linux-ouya-ouya or linux-ouya-ouya-mainline) then the boot.img will be regenerated with the new kernel. Run the following commands on device to install the updated boot.img:
For altboot.img on /sdcard:
# mkdir /data
# mount /dev/mmcblk1p9 /data
# cp /boot/boot.img-ouya-ouya /data/media/altboot.img
For boot.img on /system:
# mkdir /system
# mount /dev/mmcblk1p3 /system
# cp /boot/boot.img-ouya-ouya /system/boot.img
== Maintainer(s) ==
* rendeko
== Contributors ==
* rendeko
* ryang2678 (Decatf)
* ollieparanoid
== Links ==
* Ouya BootMenu (source)
* CWM
* CyanogenMod documentation blog
* Add mainline based kernel for Ouya
*