Linux 7.3 Introduces 8250_mxpcie Driver For Moxa PCIe Multi-Port Serial Boards

The TTY/Serial code changes for Linux 7.3 were merged this week and include dropping the dated IPWireless driver while introducing the new 8250_mxpcie driver. The new 8250_mxpcie driver is splitting out existing functionality of the 8250_pci driver so that Moxa PCIe multiport serial board support is now found in its own dedicated driver. In turn the 8250_mxpcie driver is extended to support new MUEx50-specific UART features not found in earlier hardware. There is FIFO trigger levels, automatic hardware and software flow control, interface mode switching, and other features with these newer Moxa PCIe multi-port serial adapters. While the 8250_mxpcie driver is added, the TTY/Serial pull for Linux 7.3 goes ahead and removes the IPWireless driver. The IPWireless driver was used for supporting some IPWireless branded 3G UMTS PCMCIA cards that were found in the US and some European countries. There's been no indications of active use since ~2011 and the likelihood of anyone still using the hardware is deemed "too low to justify continuing to carry the driver in the kernel." If there does happen to be any users left, the driver is simple enough it could be built as an external kernel module. The TTY code also adds VT mode validation to the vt_setactive function. Until now users could pass invalid modes for the virtual terminal and end up causing undefined VT switching behavior. The full list of TTY/Serial changes for Linux 7.3 can be found via this pull request that is already merged to Git.