CONFIG_ETRAX_SERIAL_PORT2_DMA7_IN is not available for thedefaultarchitecture x86.
Result is shown for architecture cris
default or selected kernelversion does not have config value CONFIG_ETRAX_SERIAL_PORT2_DMA7_IN.
Result is shown for kernelversion 6.7-rc3

Ser2 uses DMA7 for input


Ser2 DMA in channel
└─>Ser2 uses DMA7 for input
In linux kernel since version 2.6.25 (release Date: 2008-04-16)  
Enables the DMA7 input channel for ser2 (ttyS2).
If you do not enable DMA, an interrupt for each character will be
used when receiving data.
Normally you want to use DMA, unless you use the DMA channel for
something else.