serial rxerr

Michael Trimarchi trimarchi at gandalf.sssup.it
Wed Feb 4 13:09:11 CET 2009


Hi,

Andy Green wrote:
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> Somebody in the thread at some point said:
>
> | I'll compile it with debug set and see if there's anything obvious.
>
> The debugging stuff in samsung.c at the moment doesn't print umcon where
> AFC is enabled... I think it can mean this did not get much attention
> before now.  Also that debugging stuff does not differentiate by UART
> channel as it stands.
>
> I started up some three-letter name distro of a few days ago from SD
> Card, when I print umcon additionally from samsung.c, I never see AFC
> enabled.
>
> So I think this is wrong already, GSM port should have AFC up to protect
> against normal kind of lockouts etc.
>
> root at om-gta02:~# stty -F /dev/ttySAC0 -a
> s3c24xx_serial_startup: port=50000000 (f5000000,c050ccdc)
> requesting tx irq...
> s3c24xx_serial_startup ok
> selecting clock c04f69c8
> config: 8bits/char
> setting ulcon to 00000003, brddiv to 325, udivslot 00000000 umcon 
> 00000000
> uart: ulcon = 0x00000003, ucon = 0x00000385, ufcon = 0x00000011
> break!
> speed 9600 baud; rows 24; columns 80;
> intr = ^C; quit = ^\; erase = ^?s3c24xx_serial_stop_rx: port=c050ca24
> ; kill = ^U; eof = ^D; eol = <undef>;
> eol2 = <undef>; start = ^Q; stop = ^S; susp = ^Z; rprnt = ^R; werase = 
> ^W;
> lnext = ^V; flush = ^O; min = 1; time = 0;
> - -parenb -parodd cs8 -hupcl -cstopb cread clocal -crtscts
> - -ignbrk -brkint -ignpar -parmrk -inpck -istrip -inlcr -igncr icrnl ixon
> - -ixoff
> - -iuclc -ixany -imaxbel
> opost -olcuc -ocrnl onlcr -onocr -onlret -ofill -ofdel nl0 cr0 tab0 bs0
> vt0 ff0
> isig icanon iexten echo echoe echok -echonl -noflsh -xcase -tostop 
> -echoprt
> echoctl echoke
>
Ok, this is one problem. The other one is the interrupt latency. The 
threshold is set on 8 chars
so you have ~800us to get chars from the buffer and it is quite a lot.

Michael



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