PineNote Development/Software Tweaks

Fixing Bluetooth

Some users have noticed instability with their wireless driver. Upgrading the driver to the version provided by LibreELEC may help! To do this, download the BCM4345C0.hcd, brcmfmac43455-sdio.bin, and brcmfmac43455-sdio.txt from the libreELEC repositories and place them in the same location as your previous firmware (`/lib/firmware/brmc/`). Then rename brcmfmac43455-sdio.{txt,bin} as `brcmfmac43455-sdio.pine64,pinenote-v1.2.{txt,bin}`. If this doesn't help, ask about it in the matrix chat!

Preliminary fix for stuttering bluetooth audio

Following a fix used for the Quartz Model A (which uses the same SoC as the Pinenote), we can modify the device tree prior to building the kernel to try to mitigate poor Bluetooth audio streaming. (reference: see https://lore.kernel.org/linux-arm-kernel/20220926055435.31284-1-leo@nabam.net/T/)

Steps:

• Open arch/arm64/boot/dts/rockchip/rk3566-pinenote.dtsi
• Go to line 939, "bluetooth", under the "uart1" section
• Edit the two lines that read "device-wake-gpios" and "host-wake-gpios"; you want them to read "device-wakeup-gpios" and "host-wakeup-gpios" respectively
• Add the following line to the end of the bluetooth section (under the vddio-supply line in my .dtsi): "max-speed = <3000000>;"
• Count your zeros, don't forget your punctuation..

Caveats:

This will improve BT audio quality at least when using the AAC codec. In my experience, the quality is more than acceptable, but there are still issues apparent: occasional isolated stutters even on AAC; prohibitively frequent stutters on SBC-XQ remain. Fully resolving BT audio issues might require further changes similar to the one described above, or may alternatively be a matter of audio software settings (e. g., process priority, audio server buffer settings). Investigation ongoing.

libinput Palm Detection

See https://gitlab.com/hrdl/pinenote-shared/-/blob/main/etc/libinput/local-overrides.quirks.

libinput Touch Arbitration

Prerequisites: setup touch arbitration via udev: https://gitlab.com/hrdl/pinenote-shared/-/blob/main/etc/udev/rules.d/81-libinput-pinenote.rules

Issues and workarounds

• No resolution reported by touchscreen driver. Workaround: patch cyttsp5.c and device tree: https://gitlab.com/hrdl/linux/-/commit/f1f9eb197d3bd88c9189ab9d8fba2d03d2e13960 or set AttrSizeHint=210x157.
  • Remaining issues: the resolution is integer-valued. Due to rounding errors this leads to a reported touchscreen size of 233x155mm instead of the configured 210x157mm. This probably causes the touch arbitration rectangle to shrink slightly.
  • TODO: check whether rotation of the touchscreen and tablet also rotate libinput's coordinate system so the rectangle used for touch arbitration is rotated correctly. Preliminary investigations suggest multiple issues related to touch screen arbitration: https://gitlab.freedesktop.org/libinput/libinput/-/issues/853
• Alternatively, patch libinput to use ARBITRATION_IGNORE_ALL instead of ARBITRATION_IGNORE_RECT: https://gitlab.com/hrdl/pinenote-shared/-/blob/main/patches/libinput/0001-Make-touch-screen-arbitration-position-independent.patch