From: Robert Baldyga Date: Fri, 17 Apr 2015 06:43:09 +0000 (+0200) Subject: serial: samsung: fix serial console break X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=31c6ba97d1671b0a853197fe54a05e0b07ce2631;p=GitHub%2FLineageOS%2FG12%2Fandroid_kernel_amlogic_linux-4.9.git serial: samsung: fix serial console break This patch fixes problems with serial console break. When function s3c64xx_serial_startup() was started while serial console has been working, it caused lose of characters written to TX FIFO. This effect was particularly observable with systemd, which closes serial port every time when it's not currently needed, hence function s3c64xx_serial_startup() is called quite often there. To fix this problem we avoid resetting TX FIFO if port is used as serial console. Example of broken console log: [ 1086.7 Expecting device dev-ttySAC1.device... [ 1086.[ OK ] Reached target Paths. [ 1086.756416] s[ OK ] Reached target Swap. [ 1086.776413] systemd[1]: Reached target Swap. [ 1086.776642] systemd[1]: Starting Root Slice. [ 5.53403[ OK ] Created slice Root Slice. [ 5.548433] systemd[1]: Create[ OK ] Created slice User and Session Slice. [ 5.568414] sys[ OK ] Listening on /dev/initctl Compatibility Named Pipe. [ 5.588388] s[ OK ] Listening on Delayed Shutdown Socket. [ 5.608376] sy[ OK ] Listening on Journal Socket (/dev/log). [ 5.628361] [ OK ] Listening on udev Kernel Socket. [ 5.648357] s[ OK ] Listening on udev Control Socket. [ 5.668353] s[ OK ] Listening on Journal Socket. [ 5.688366] systemd[1]: Listeni[ OK ] Created slice System Slice. [ 5.708393] Mounting Temporary Directory... [ 7139.067436] Starting prepare device daemon... [ 7139.091726] sy Starting Generate environment from /etc/profile.d... [ 5.792867] system Starting Create Static Device Nodes in /dev... [ 7848.718 Mounting Debug File System... [ 7848.7384 Mounting Configuration File System... [ 5.852 Starting Apply Kernel Variables... [ 5.8720 Starting Setup Virtual Console... [ 7848.798 Starting udev Coldplug all Devices... [ 7848.817 Starting Journal Service... [ OK ] Started Journal Service. [ 7848.854222] s[ OK ] Reached target Slices. Starting Remount Root and Kernel File Systems... [ OK ] Mounted Configuration File System. Reported-by: Chanwoo Choi Signed-off-by: Robert Baldyga Reviewed-by: Peter Hurley Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/tty/serial/samsung.c b/drivers/tty/serial/samsung.c index cf08876922f1..a0ae942d9562 100644 --- a/drivers/tty/serial/samsung.c +++ b/drivers/tty/serial/samsung.c @@ -1068,8 +1068,9 @@ static int s3c64xx_serial_startup(struct uart_port *port) spin_lock_irqsave(&port->lock, flags); ufcon = rd_regl(port, S3C2410_UFCON); - ufcon |= S3C2410_UFCON_RESETRX | S3C2410_UFCON_RESETTX | - S5PV210_UFCON_RXTRIG8; + ufcon |= S3C2410_UFCON_RESETRX | S5PV210_UFCON_RXTRIG8; + if (!uart_console(port)) + ufcon |= S3C2410_UFCON_RESETTX; wr_regl(port, S3C2410_UFCON, ufcon); enable_rx_pio(ourport);