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authorPeter Hurley <peter@hurleysoftware.com>2014-06-16 14:10:41 +0200
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2014-06-19 22:04:52 +0200
commitef8b9ddcb45fa3b1e11acd72be2398001e807d14 (patch)
treebc3e882cdbdb0e34d1506534596be4af49e17d61 /drivers/tty/serial/mpsc.c
parentserial: samsung: Fix build error (diff)
downloadlinux-ef8b9ddcb45fa3b1e11acd72be2398001e807d14.tar.xz
linux-ef8b9ddcb45fa3b1e11acd72be2398001e807d14.zip
serial: Fix IGNBRK handling
If IGNBRK is set without either BRKINT or PARMRK set, some uart drivers send a 0x00 byte for BREAK without the TTYBREAK flag to the line discipline, when it should send either nothing or the TTYBREAK flag set. This happens because the read_status_mask masks out the BI condition, which uart_insert_char() then interprets as a normal 0x00 byte. SUS v3 is clear regarding the meaning of IGNBRK; Section 11.2.2, General Terminal Interface - Input Modes, states: "If IGNBRK is set, a break condition detected on input shall be ignored; that is, not put on the input queue and therefore not read by any process." Fix read_status_mask to include the BI bit if IGNBRK is set; the lsr status retains the BI bit if a BREAK is recv'd, which is subsequently ignored in uart_insert_char() when masked with the ignore_status_mask. Affected drivers: 8250 - all serial_txx9 mfd amba-pl010 amba-pl011 atmel_serial bfin_uart dz ip22zilog max310x mxs-auart netx-serial pnx8xxx_uart pxa sb1250-duart sccnxp serial_ks8695 sirfsoc_uart st-asc vr41xx_siu zs sunzilog fsl_lpuart sunsab ucc_uart bcm63xx_uart sunsu efm32-uart pmac_zilog mpsc msm_serial m32r_sio Unaffected drivers: omap-serial rp2 sa1100 imx icom Annotated for fixes: altera_uart mcf Drivers without break detection: 21285 xilinx-uartps altera_jtaguart apbuart arc-uart clps711x max3100 uartlite msm_serial_hs nwpserial lantiq vt8500_serial Unknown: samsung mpc52xx_uart bfin_sport_uart cpm_uart/core Fixes: Bugzilla #71651, '8250_core.c incorrectly handles IGNBRK flag' Reported-by: Ivan <athlon_@mail.ru> Signed-off-by: Peter Hurley <peter@hurleysoftware.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/tty/serial/mpsc.c')
-rw-r--r--drivers/tty/serial/mpsc.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/tty/serial/mpsc.c b/drivers/tty/serial/mpsc.c
index e30a3ca3cea3..759c6a6fa74a 100644
--- a/drivers/tty/serial/mpsc.c
+++ b/drivers/tty/serial/mpsc.c
@@ -1458,7 +1458,7 @@ static void mpsc_set_termios(struct uart_port *port, struct ktermios *termios,
pi->port.read_status_mask |= SDMA_DESC_CMDSTAT_PE
| SDMA_DESC_CMDSTAT_FR;
- if (termios->c_iflag & (BRKINT | PARMRK))
+ if (termios->c_iflag & (IGNBRK | BRKINT | PARMRK))
pi->port.read_status_mask |= SDMA_DESC_CMDSTAT_BR;
/* Characters/events to ignore */