Multi-port serial cards like those from StarTech or B&H Photo Video use these chips to add COM ports to desktops.
The kernel performs a "UART type check" by writing to the FIFO control register. If the device correctly handles 128-byte FIFOs and reports via UART_EXAR_98 or similar flags, the kernel loads the 8250_exar driver. 16c95x Serial Port Driver
Most developers cut their teeth on the 16550 UART—a 16-byte FIFO (First-In-First-Out) device that was revolutionary in the early 1990s. The 16c95x, however, is a different beast. It is a high-performance, multi-channel UART. Variants like the 16c954 or 16c955 offer two, four, or even eight independent serial ports on a single chip. Multi-port serial cards like those from StarTech or
The moment a character arrives or the transmit FIFO empties, the 16c95x asserts an interrupt. The driver’s ISR must perform a deterministic ballet: Most developers cut their teeth on the 16550