tty/serial: Need clarification on Support for 4+M Baudrate
From: Alan Cox <hidden>
Date: 2012-01-12 14:38:28
Also in:
linux-serial, lkml
From: Alan Cox <hidden>
Date: 2012-01-12 14:38:28
Also in:
linux-serial, lkml
On Thu, 12 Jan 2012 15:20:46 +0100 Rajanikanth H V [off-list ref] wrote:
Alan, FYI: I am not using application, rather I have a Bluetooth driver invoking encode_baud_rate(...), please find log below. I made sure that c_ispeed = c_ospeed = 4.05M Baud, however I see tty_termios_encode_baud_rate(...) is normalizing to 4.0 manual trace log below: ====================================================================================== 4.05M Arbitrary Baud Setting Sequence: [ 9.664703] alloc_set_baud_rate_cmd Setting arbitrary baudrate using BOTHER baudrate:89 c_cflag:020000016262 [ 9.774658] XXXXXX_hci_uart_set_baudrate c_cflag:020000016262 baud:4050000
4050000 seems a bit odd - you want cflag&CBAUD == BOTHER so I'd expect the low bits to end rather different things to 6262 ? So something like struct ktermios new = *tty->termios; new.c_cflag &= ~(CBAUD|CIBAUD); new.c_cflag |= BOTHER; new.c_ispeed = 4050000; new.c_ospeed = 4050000; tty_set_termios(tty, &new); /* Can sleep */ /* Returned new will now hold actual values selected */ should do the trick providing the low level driver supports the rate. Alan