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* Bug in serial.c
@ 2001-04-19 15:32 Marc Karasek
  2001-04-19 15:38 ` Disconnect
                   ` (3 more replies)
  0 siblings, 4 replies; 6+ messages in thread
From: Marc Karasek @ 2001-04-19 15:32 UTC (permalink / raw)
  To: 'linux-kernel@vger.kernel.org'

I am doing some embedded development with the 2.4.x series and have noticed
a few things..

1) In 2.4.2 in order to compile with module support you also had to turn on
smp support.  This has been fixed in the 2.4.3 release.  This bloated the
kernel image to 600k+ which in an embedded world is not a good thing :-)

2) In 2.4.3 the console port using ttySX is broken.  It dumps fine to the
terminal but when you get to a point of entering data (login, configuration
scripts, etc) the terminal does not accept any input.  

So far I have been able to debug to the point where I see that the kernel is
receiving the characters from the serial.c driver.  But it never echos them
or does anything else with them.  I will continue to look into this at this
end.  

I was also wondering if anyone else has seen this or if a patch is avail for
this bug??

Marc Karasek
Sr. Firmware Engineer
iVivity Inc
marc_karasek@ivivity.com  

^ permalink raw reply	[flat|nested] 6+ messages in thread
* RE: Bug in serial.c
@ 2001-04-19 16:18 Marc Karasek
  0 siblings, 0 replies; 6+ messages in thread
From: Marc Karasek @ 2001-04-19 16:18 UTC (permalink / raw)
  To: 'Richard B. Johnson ', Marc Karasek
  Cc: 'linux-kernel@vger.kernel.org'

I think maybe we have a miscommunication here..  I am not running any apps
(yet) all I am trying to do is get it to boot up under 2.4.3.  The
apps/daemons/modules are the next step.  I am just booting the standard
kernel to a login prompt.  (I am usng busybox for init.)  Before a login
prompt a script is run as part of inittab to setup the eth0 port, etc...
This requires some input from the console (in this case ttyS0).  It is at
this point that 2.4.2 works (accepts input and lets the script continue)
2.4.3 just sits there, you can bang on the keys all you want :-(  


Also, I did a diff between serial.c in 2.4.2 & 2.4.3 and there are a lot of
changes...  

 

-----Original Message-----
From: Richard B. Johnson
To: Marc Karasek
Sent: 4/19/01 12:07 PM
Subject: RE: Bug in serial.c 

On Thu, 19 Apr 2001, Marc Karasek wrote:

>  Did something change between 2.4.2 & 2.4.3? Under 2.4.2 I did not
have to
> init the terminal (are you refering to the host or client side?) and
just
> accepted the defaults (9600, 8n1) which was fine for debug and
terminal I/O.
> 
> 
> My issue is with 2.4.2 it works with 2.4.3 (same .config) it does not.
So
> in my mind this is a bug of some type.....  :-) 
> 
> Which kernel are you using in your embedded project??
> 

I have conditional compiles for 2.2.17 to 2.2.19 plus 2.4.1, 2.4.2,
2.4.3, 2.4.4-pre(something, maybe 4).

There have been a lot of changes (and bugs), but Serial TTY I/O has
not been one of them -- and I use RS-232C with ANSI escape sequences
(vt101 DEC), because we don't have a screen-card or a keyboard. I
would have been first to notice.

Of course my code DID initialize the terminal from the start, if yours
didn't, the defaults may have changed. There was an old bug with
flow-control (an X-OFF stuck-state), that required the terminal
to opened and closed twice to clear. I still have the work-around
in the init code.


/*-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
-=-*/
/*
 *  Since we __are__ init, we have to everything that is necessary to
 *  startup and maintain the system.
 */
int main(int argc, char *argv[])
{
    MEM *mem;
    size_t i;
    int fd, flags;
    speed_t baud;
    if((mem = (MEM *) malloc(sizeof(MEM))) == NULL)
        ERRORS(Malloc);
    strcpy(argv[0], "Platinum");
    argv[0] = mem->argv0;
    argv[1] = mem->argv1;
    argv[2] = NULL;
/*-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=-=
-=-*/
/*
 *  We may have failed to open an initial console. Therefore, we do the
 *  terminal stuff over from scratch.
 */
    clr(&mem->st,  sizeof(struct termios));
    mem->st.c_cc[VINTR]    = (char) 'C' - 64;
    mem->st.c_cc[VQUIT]    = (char) '\\'- 64;
    mem->st.c_cc[VERASE]   = (char) '?' + 64;
    mem->st.c_cc[VKILL]    = (char) 'U' - 64;
    mem->st.c_cc[VEOF]     = (char) 'D' - 64;
    mem->st.c_cc[VTIME]    = (char)  0;
    mem->st.c_cc[VMIN]     = (char)  1;
    mem->st.c_cc[VSWTC]    = (char) '@' - 64;
    mem->st.c_cc[VSTART]   = (char) 'Q' - 64;
    mem->st.c_cc[VSTOP]    = (char) 'S' - 64;
    mem->st.c_cc[VSUSP]    = (char) 'Z' - 64;
    mem->st.c_cc[VEOL]     = (char) '@' - 64;
    mem->st.c_cc[VREPRINT] = (char) 'R' - 64;
    mem->st.c_cc[VDISCARD] = (char) 'O' - 64;
    mem->st.c_cc[VWERASE]  = (char) 'W' - 64;
    mem->st.c_cc[VLNEXT]   = (char) 'V' - 64;
    mem->st.c_cc[VEOL2]    = (char) '@' - 64;
    mem->st.c_oflag = OPOST|ONLCR;
    mem->st.c_iflag = ICRNL|IXON;
    mem->st.c_lflag =
ISIG|ICANON|ECHO|ECHOE|ECHOK|ECHOCTL|ECHOKE|IEXTEN;
    mem->st.c_cflag = B9600|CS8|CREAD|HUPCL|CLOCAL;
/*
 *  Because of a bug in the Linux 2.4.0 terminal driver, we have to do
 *  this twice to get the flow-control turned off.
 */
    for(i=0; i< 2; i++)
    {
        (void)close(STDIN_FILENO);
        (void)close(STDOUT_FILENO);
        (void)close(STDERR_FILENO);
        if((fd = open(stdcmd, O_RDWR|O_NDELAY, 0)) < 0)
            fd = open(Altcons, O_RDWR|O_NDELAY);
        if((flags = fcntl(fd, F_GETFL, 0)) == FAIL)
            ERRORS(Fcntl);
        flags &= ~O_NDELAY;
        if(fcntl(fd, F_SETFL, flags) == FAIL)
            ERRORS(Fcntl);
        if(!!fd)
        {
            if(dup2(fd, STDIN_FILENO) == FAIL)
                ERRORS(Dup2);
            if(dup2(fd, STDOUT_FILENO) == FAIL)
                ERRORS(Dup2);
            if(dup2(fd, STDERR_FILENO) == FAIL)
                ERRORS(Dup2);
            if(fd > 2) (void)close(fd);
        }
        else                         /* fd is STDIN_FILENO  */
        {
            if(dup(fd) == FAIL)      /* Make STDOUT_FILENO  */
                ERRORS(Dup);
            if(dup(fd) == FAIL)      /* Make STDERR_FILENO  */
                ERRORS(Dup);
        }
        if(tcflush(STDIN_FILENO, TCIFLUSH) < 0)
            ERRORS(Tcflush);
        if(tcsetattr(STDIN_FILENO, TCSANOW, &mem->st) < 0)
            ERRORS(Tcsetattr);
    }



Cheers,
Dick Johnson

Penguin : Linux version 2.4.1 on an i686 machine (799.53 BogoMips).

"Memory is like gasoline. You use it up when you are running. Of
course you get it all back when you reboot..."; Actual explanation
obtained from the Micro$oft help desk.


^ permalink raw reply	[flat|nested] 6+ messages in thread
end of thread, other threads:[~2001-04-20 16:33 UTC | newest]

Thread overview: 6+ messages (download: mbox.gz follow: Atom feed
-- links below jump to the message on this page --
2001-04-19 15:32 Bug in serial.c Marc Karasek
2001-04-19 15:38 ` Disconnect
2001-04-19 15:43 ` Richard B. Johnson
2001-04-19 23:10 ` Steven Walter
2001-04-20 16:31 ` Fabrice Gautier
  -- strict thread matches above, loose matches on Subject: below --
2001-04-19 16:18 Marc Karasek

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