Hello,
v6.1.14 on a Phytec phyBoard Segin i.MX 6ULL based board [0] is losing bytes on UART RX.
imx_v6_v7_defconfig was used.
Minimalistic test to reproduce the issue:
1) Connect imx6ull UART with another machine
2) imx6ull$ stty -F /dev/ttymxc0 115200 raw; cat /dev/ttymcx0
3) othermachine$ stty -F /dev/USB0 115200 raw;
echo "1234567890abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ$%-.,()/&" > /dev/ttyUSB0
Expected result:
imx6ull: 1234567890abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ$%-.,()/&
Seen result (Many times, not always):
imx6ull: 1234567890abcdefghijklmnopqrstuvABCDEFGHIJKLMNOPQRSTUVWXYZ$%-.,()/&
or
imx6ull: 1234567890abcdefghijklmnopqrstuvBCDEFGHIJKLMNOPQRSTUVWXYZ$%-.,()/&
or
...
Setting scaling_governor to performance seems to be a workaround for this problem - but:
We are normally using the PREMPT_RT patch [1], and with this workaround bytes will still be lost
Any hints how to track this down further?
[0] https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/tree/arch/arm/boot/dts/imx6ull-phytec-segin-ff-rdk-nand.dts?h=v6.1.14
[1] https://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-rt-devel.git/tag/?h=v6.1.12-rt7
