close /dev/console casue 30seconds' hang

close /dev/console casue 30seconds' hang

[Yi Qingliang]

I'm running 3.6.9 kernel on my s3c2442 board.
the sysvinit freeze 30seconds after print out "INIT:",
and then freeze 30seconds after print out "version 2.88 booting".
I checked it's code, the 'close(fd)' should be responsible for that.

same binary running well on mini2440(s3c2440 board).
Through several days hard work, I got the root cause.
the close called wait_until_sent with timeout(30seconds).
the uart clock source selection is different.
although both of the two boards selected 'pclk',
related register: UCON0[11:10] 0x50000004
s3c2440 use '10', s3c2442 use '00'.

on s3c2440, the '10' is selected in initialalize stage. on s3c2442, it
can't find propriate clock, so use default value '00'.

in initialize stage, it will found 'clk_uart_baud2", but not on s3c2442. I
checked 'arch/arm/mach-s3c24xx/clock-s3c2440.c', it is only registered
for s3c2440_subsys,
but not for s3c2442_sys. after registered 's3c2440_clk_lookup' for
s3c2442_subsys, everything OK.

problem:
1. I don't know the different between 00 and 10 of pck in register
UCON0[11:10].
2. why kernel code have not registered s3c2440_clk_lookup for s3c2442? and 
also
dma-s3c2440.c.

I checked 'arch/arm/mach-s3c24xx/s3c2442.c', it is for the s3c2442's clock,
but why the file name is not 'clock-s3c2442.c'? an it only contain cam
related
clock, no uart related clock.

Re: close /dev/console casue 30seconds' hang

[Denis 'GNUtoo' Carikli]

On Sun, 20 Jan 2013 19:28:42 +0800
Yi Qingliang <niqingliang2003@gmail.com> wrote:

> I'm running 3.6.9 kernel on my s3c2442 board.
> the sysvinit freeze 30seconds after print out "INIT:",
> and then freeze 30seconds after print out "version 2.88 booting".
> I checked it's code, the 'close(fd)' should be responsible for that.
I had the exact same problem while trying to boot a recent
mainline kernel on the GTA02.

I tried to bisect it many times but I failed because the problem was in
a reagion that I had to skip...

Denis.

Re: close /dev/console casue 30seconds' hang

[Yi Qingliang]

On Sunday, January 20, 2013 01:00:25 PM Denis 'GNUtoo' Carikli wrote:
> On Sun, 20 Jan 2013 19:28:42 +0800
> 
> Yi Qingliang <niqingliang2003@gmail.com> wrote:
> > I'm running 3.6.9 kernel on my s3c2442 board.
> > the sysvinit freeze 30seconds after print out "INIT:",
> > and then freeze 30seconds after print out "version 2.88 booting".
> > I checked it's code, the 'close(fd)' should be responsible for that.
> 
> I had the exact same problem while trying to boot a recent
> mainline kernel on the GTA02.
> 
> I tried to bisect it many times but I failed because the problem was in
> a reagion that I had to skip...
maybe we should register the uart related clock info ( clock-s3c2440.c ) for 
s3c2442.
although I resolved it, but I don't know the different between 00 and 10, they 
are all pclk. (UCON[11:10]),
maybe the samsung.c or clock-s3c2440.c's author can tell us.
> 
> Denis.

Re: close /dev/console casue 30seconds' hang

[Yi Qingliang]

n Sunday, January 20, 2013 01:00:25 PM Denis 'GNUtoo' Carikli wrote:
> On Sun, 20 Jan 2013 19:28:42 +0800
> 
> Yi Qingliang <niqingliang2003@gmail.com> wrote:
> > I'm running 3.6.9 kernel on my s3c2442 board.
> > the sysvinit freeze 30seconds after print out "INIT:",
> > and then freeze 30seconds after print out "version 2.88 booting".
> > I checked it's code, the 'close(fd)' should be responsible for that.
> 
> I had the exact same problem while trying to boot a recent
> mainline kernel on the GTA02.
> 
> I tried to bisect it many times but I failed because the problem was in
> a reagion that I had to skip...
I also tried to open INITDEBUG and DEBUG in sysvinit's init.h, can solve this 
problem.

the INITDEBUG will fork a process, and then the close(fd) will not call 
release in tty driver.

I have checked the state of uart fifo, if the pclk is 00, it looks like the fifo 
works abnormally.
> 
> Denis.

Re: close /dev/console casue 30seconds' hang

[Yi Qingliang]

On Sunday, January 20, 2013 01:00:25 PM Denis 'GNUtoo' Carikli wrote:
> On Sun, 20 Jan 2013 19:28:42 +0800
> 
> Yi Qingliang <niqingliang2003@gmail.com> wrote:
> > I'm running 3.6.9 kernel on my s3c2442 board.
> > the sysvinit freeze 30seconds after print out "INIT:",
> > and then freeze 30seconds after print out "version 2.88 booting".
> > I checked it's code, the 'close(fd)' should be responsible for that.
> 
> I had the exact same problem while trying to boot a recent
> mainline kernel on the GTA02.
do you mean there is no problem for early version kernel?
> 
> I tried to bisect it many times but I failed because the problem was in
> a reagion that I had to skip...
> 
> Denis.

Re: close /dev/console casue 30seconds' hang

[Denis 'GNUtoo' Carikli]

On Sun, 20 Jan 2013 20:57:16 +0800
Yi Qingliang <niqingliang2003@gmail.com> wrote:

> o you mean there is no problem for early version kernel?
yes, but for really old versions such as 3.2 and earlier.

Denis.

Re: close /dev/console casue 30seconds' hang

[Yi Qingliang]

On Sunday, January 20, 2013 04:27:43 PM Denis 'GNUtoo' Carikli wrote:
> On Sun, 20 Jan 2013 20:57:16 +0800
> 
> Yi Qingliang <niqingliang2003@gmail.com> wrote:
> > o you mean there is no problem for early version kernel?
> 
> yes, but for really old versions such as 3.2 and earlier.
Can anyone tell me the difference between '00' and '10' about UCON[11:10] clock 
source selection (s3c2442)?
> Denis.
-- 
Nanjing Jilong
Yi Qingliang
niqingliang2003@gmail.com