Hello, It reminds me about this: https://marc.info/?l=linux-serial&m=166479501704202&w=2 HTH, -- Sergey Gerz Burak LCPF-CH <Burak.Gerz@xxxxxx> writes: > 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
