From ef8b9ddcb45fa3b1e11acd72be2398001e807d14 Mon Sep 17 00:00:00 2001 From: Peter Hurley Date: Mon, 16 Jun 2014 08:10:41 -0400 Subject: 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 Signed-off-by: Peter Hurley Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/m32r_sio.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'drivers/tty/serial/m32r_sio.c') diff --git a/drivers/tty/serial/m32r_sio.c b/drivers/tty/serial/m32r_sio.c index 9cd9b4eba9fc..68f2c53e0b54 100644 --- a/drivers/tty/serial/m32r_sio.c +++ b/drivers/tty/serial/m32r_sio.c @@ -737,7 +737,7 @@ static void m32r_sio_set_termios(struct uart_port *port, up->port.read_status_mask = UART_LSR_OE | UART_LSR_THRE | UART_LSR_DR; if (termios->c_iflag & INPCK) up->port.read_status_mask |= UART_LSR_FE | UART_LSR_PE; - if (termios->c_iflag & (BRKINT | PARMRK)) + if (termios->c_iflag & (IGNBRK | BRKINT | PARMRK)) up->port.read_status_mask |= UART_LSR_BI; /* -- cgit From c557d392fbf5badd693ea1946a4317c87a26a716 Mon Sep 17 00:00:00 2001 From: Peter Hurley Date: Sun, 6 Jul 2014 11:29:52 -0400 Subject: serial: Test for no tx data on tx restart Commit 717f3bbab3c7628736ef738fdbf3d9a28578c26c, 'serial_core: Fix conditional start_tx on ring buffer not empty' exposes an incorrect assumption in several drivers' start_tx methods; the tx ring buffer can, in fact, be empty when restarting tx while performing flow control. Affected drivers: sunsab.c ip22zilog.c pmac_zilog.c sunzilog.c m32r_sio.c imx.c Other in-tree serial drivers either are not affected or already test for empty tx ring buffer before transmitting. Test for empty tx ring buffer in start_tx() method, after transmitting x_char (if applicable). Reported-by: Aaro Koskinen Cc: Seth Bollinger Cc: "David S. Miller" Cc: Sam Ravnborg Cc: Thomas Bogendoerfer Signed-off-by: Peter Hurley Cc: stable # 3.15 Signed-off-by: Greg Kroah-Hartman --- drivers/tty/serial/m32r_sio.c | 8 +++++--- 1 file changed, 5 insertions(+), 3 deletions(-) (limited to 'drivers/tty/serial/m32r_sio.c') diff --git a/drivers/tty/serial/m32r_sio.c b/drivers/tty/serial/m32r_sio.c index 68f2c53e0b54..5702828fb62e 100644 --- a/drivers/tty/serial/m32r_sio.c +++ b/drivers/tty/serial/m32r_sio.c @@ -266,9 +266,11 @@ static void m32r_sio_start_tx(struct uart_port *port) if (!(up->ier & UART_IER_THRI)) { up->ier |= UART_IER_THRI; serial_out(up, UART_IER, up->ier); - serial_out(up, UART_TX, xmit->buf[xmit->tail]); - xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1); - up->port.icount.tx++; + if (!uart_circ_empty(xmit)) { + serial_out(up, UART_TX, xmit->buf[xmit->tail]); + xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1); + up->port.icount.tx++; + } } while((serial_in(up, UART_LSR) & UART_EMPTY) != UART_EMPTY); #else -- cgit