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bca476139d
When controlling an industrial radio modem it can be necessary to manipulate the handshake lines in order to control the radio modem's transmitter, from userspace. The transmitter should not be turned off before all characters have been transmitted. serial8250_tx_empty() was reporting that all characters were transmitted before they actually were. === Discovered in parallel with more testing and analysis by Kees Schoenmakers as follows: I ran into an NetMos 9835 serial pci board which behaves a little different than the standard. This type of expansion board is very common. "Standard" 8250 compatible devices clear the 'UART_LST_TEMT" bit together with the "UART_LSR_THRE" bit when writing data to the device. The NetMos device does it slightly different I believe that the TEMT bit is coupled to the shift register. The problem is that after writing data to the device and very quickly after that one does call serial8250_tx_empty, it returns the wrong information. My patch makes the test more robust (and solves the problem) and it does not affect the already correct devices. Alan: We may yet need to quirk this but now we know which chips we have a way to do that should we find this breaks some other 8250 clone with dodgy THRE. Signed-off-by: Dick Hollenbeck <dick@softplc.com> Signed-off-by: Alan Cox <alan@linux.intel.com> Cc: Kees Schoenmakers <k.schoenmakers@sigmae.nl> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Cc: stable <stable@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de> |
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| .. | ||
| cpm_uart | ||
| jsm | ||
| 8250_accent.c | ||
| 8250_acorn.c | ||
| 8250_boca.c | ||
| 8250_early.c | ||
| 8250_exar_st16c554.c | ||
| 8250_fourport.c | ||
| 8250_gsc.c | ||
| 8250_hp300.c | ||
| 8250_hub6.c | ||
| 8250_mca.c | ||
| 8250_pci.c | ||
| 8250_pnp.c | ||
| 8250.c | ||
| 8250.h | ||
| 21285.c | ||
| 68328serial.c | ||
| 68328serial.h | ||
| 68360serial.c | ||
| amba-pl010.c | ||
| amba-pl011.c | ||
| apbuart.c | ||
| apbuart.h | ||
| atmel_serial.c | ||
| bcm63xx_uart.c | ||
| bfin_5xx.c | ||
| bfin_sport_uart.c | ||
| bfin_sport_uart.h | ||
| clps711x.c | ||
| crisv10.c | ||
| crisv10.h | ||
| dz.c | ||
| dz.h | ||
| icom.c | ||
| icom.h | ||
| imx.c | ||
| ioc3_serial.c | ||
| ioc4_serial.c | ||
| ip22zilog.c | ||
| ip22zilog.h | ||
| Kconfig | ||
| kgdboc.c | ||
| m32r_sio_reg.h | ||
| m32r_sio.c | ||
| m32r_sio.h | ||
| Makefile | ||
| max3100.c | ||
| mcf.c | ||
| mpc52xx_uart.c | ||
| mpsc.c | ||
| msm_serial.c | ||
| msm_serial.h | ||
| mux.c | ||
| netx-serial.c | ||
| nwpserial.c | ||
| of_serial.c | ||
| pmac_zilog.c | ||
| pmac_zilog.h | ||
| pnx8xxx_uart.c | ||
| pxa.c | ||
| s3c24a0.c | ||
| s3c2400.c | ||
| s3c2410.c | ||
| s3c2412.c | ||
| s3c2440.c | ||
| s3c6400.c | ||
| sa1100.c | ||
| samsung.c | ||
| samsung.h | ||
| sb1250-duart.c | ||
| sc26xx.c | ||
| serial_core.c | ||
| serial_cs.c | ||
| serial_ks8695.c | ||
| serial_lh7a40x.c | ||
| serial_txx9.c | ||
| sh-sci.c | ||
| sh-sci.h | ||
| sn_console.c | ||
| suncore.c | ||
| suncore.h | ||
| sunhv.c | ||
| sunsab.c | ||
| sunsab.h | ||
| sunsu.c | ||
| sunzilog.c | ||
| sunzilog.h | ||
| timbuart.c | ||
| timbuart.h | ||
| uartlite.c | ||
| ucc_uart.c | ||
| vr41xx_siu.c | ||
| zs.c | ||
| zs.h | ||