A PPC kernel issue with UART ??

A PPC kernel issue with UART ??

[JohnsonCheng]

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Dear All,

 

I meet a wired UART problem on linux-2.6 with MPC8241 chip.

 

My Environment is as following: 

CPU: MPC8241

Linux: 2.6.12.3

COM1 offset: 0x4500, COM2 offset: 0x4600

 

When I booting my rootfs, it hangs at following message:

RAMDISK: Compressed image found at block 0

VFS: Mounted root (ext2 filesystem) readonly.

Freeing unused kernel memory: 104k init

EXT2-fs warning: checktime reached, running e2fsck is recommended

 

I had add printk in tty_write() of drivers/char/tty_io.c, the message from
rootfs have printed.

The conclusion is that message can be printed by printk() in linux kernel,
but can't be printed by printf() in user mode. I think it must be something
wrong for my UART configurations, does anybody know it??

 

 

Best Regards,

Johnson Cheng


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Re: A PPC kernel issue with UART ??

[Daniel Ann]

Johnson,

You know what? I've had the exact same problem only day or two ago. I
think the mail subject was "serial console" or something similar. Have
a read at it.

BTW, My problem was with interrupt setting.
Daniel.

On 8/2/05, JohnsonCheng <johnsoncheng@qnap.com.tw> wrote:
>=20
>=20
> Dear All,
>=20
> =20
>=20
> I meet a wired UART problem on linux-2.6 with MPC8241 chip.
>=20
> =20
>=20
> My Environment is as following:=20
>=20
> CPU: MPC8241
>=20
> Linux: 2.6.12.3
>=20
> COM1 offset: 0x4500, COM2 offset: 0x4600
>=20
> =20
>=20
> When I booting my rootfs, it hangs at following message:
>=20
> RAMDISK: Compressed image found at block 0
>=20
> VFS: Mounted root (ext2 filesystem) readonly.
>=20
> Freeing unused kernel memory: 104k init
>=20
> EXT2-fs warning: checktime reached, running e2fsck is recommended
>=20
> =20
>=20
> I had add printk in tty_write() of drivers/char/tty_io.c, the message fro=
m
> rootfs have printed.
>=20
> The conclusion is that message can be printed by printk() in linux kernel=
,
> but can't be printed by printf() in user mode. I think it must be somethi=
ng
> wrong for my UART configurations, does anybody know it??
>=20
> =20
>=20
> =20
>=20
> Best Regards,
>=20
> Johnson Cheng
> _______________________________________________
> Linuxppc-embedded mailing list
> Linuxppc-embedded@ozlabs.org
> https://ozlabs.org/mailman/listinfo/linuxppc-embedded
>=20
>=20


--=20
Daniel

RE: A PPC kernel issue with UART ??

[JohnsonCheng]

Actually, I had reviews all article about "serial console", just know I have
to use LEVEL for interrupt, not EDGE. Unfortunately the default interrupt
setting for kernel is with LEVEL, IRQ_SENSE_LEVEL, I think I don't need to
modify it.
But I found I add ASYNC_SKIP_TEST flag to UART in sandpoint.h can fix my
problem.

Thanks,
Johnson Cheng

-----Original Message-----
From: linuxppc-embedded-bounces@ozlabs.org
[mailto:linuxppc-embedded-bounces@ozlabs.org] On Behalf Of Daniel Ann
Sent: Wednesday, August 03, 2005 8:22 AM
To: JohnsonCheng
Cc: linuxppc-embedded@ozlabs.org
Subject: Re: A PPC kernel issue with UART ??

Johnson,

You know what? I've had the exact same problem only day or two ago. I
think the mail subject was "serial console" or something similar. Have
a read at it.

BTW, My problem was with interrupt setting.
Daniel.

On 8/2/05, JohnsonCheng <johnsoncheng@qnap.com.tw> wrote:
> 
> 
> Dear All,
> 
>  
> 
> I meet a wired UART problem on linux-2.6 with MPC8241 chip.
> 
>  
> 
> My Environment is as following: 
> 
> CPU: MPC8241
> 
> Linux: 2.6.12.3
> 
> COM1 offset: 0x4500, COM2 offset: 0x4600
> 
>  
> 
> When I booting my rootfs, it hangs at following message:
> 
> RAMDISK: Compressed image found at block 0
> 
> VFS: Mounted root (ext2 filesystem) readonly.
> 
> Freeing unused kernel memory: 104k init
> 
> EXT2-fs warning: checktime reached, running e2fsck is recommended
> 
>  
> 
> I had add printk in tty_write() of drivers/char/tty_io.c, the message from
> rootfs have printed.
> 
> The conclusion is that message can be printed by printk() in linux kernel,
> but can't be printed by printf() in user mode. I think it must be
something
> wrong for my UART configurations, does anybody know it??
> 
>  
> 
>  
> 
> Best Regards,
> 
> Johnson Cheng
> _______________________________________________
> Linuxppc-embedded mailing list
> Linuxppc-embedded@ozlabs.org
> https://ozlabs.org/mailman/listinfo/linuxppc-embedded
> 
> 


-- 
Daniel
_______________________________________________
Linuxppc-embedded mailing list
Linuxppc-embedded@ozlabs.org
https://ozlabs.org/mailman/listinfo/linuxppc-embedded

Re: A PPC kernel issue with UART ??

[Daniel Ann]

A Ha. That's the question I've asked kumar earlier today. Having
inserted that myself it worked also. Still wondering why tho...

On 8/3/05, JohnsonCheng <johnsoncheng@qnap.com.tw> wrote:
> Actually, I had reviews all article about "serial console", just know I h=
ave
> to use LEVEL for interrupt, not EDGE. Unfortunately the default interrupt
> setting for kernel is with LEVEL, IRQ_SENSE_LEVEL, I think I don't need t=
o
> modify it.
> But I found I add ASYNC_SKIP_TEST flag to UART in sandpoint.h can fix my
> problem.
>=20
> Thanks,
> Johnson Cheng
>=20
> -----Original Message-----
> From: linuxppc-embedded-bounces@ozlabs.org
> [mailto:linuxppc-embedded-bounces@ozlabs.org] On Behalf Of Daniel Ann
> Sent: Wednesday, August 03, 2005 8:22 AM
> To: JohnsonCheng
> Cc: linuxppc-embedded@ozlabs.org
> Subject: Re: A PPC kernel issue with UART ??
>=20
> Johnson,
>=20
> You know what? I've had the exact same problem only day or two ago. I
> think the mail subject was "serial console" or something similar. Have
> a read at it.
>=20
> BTW, My problem was with interrupt setting.
> Daniel.
>=20
> On 8/2/05, JohnsonCheng <johnsoncheng@qnap.com.tw> wrote:
> >
> >
> > Dear All,
> >
> >
> >
> > I meet a wired UART problem on linux-2.6 with MPC8241 chip.
> >
> >
> >
> > My Environment is as following:
> >
> > CPU: MPC8241
> >
> > Linux: 2.6.12.3
> >
> > COM1 offset: 0x4500, COM2 offset: 0x4600
> >
> >
> >
> > When I booting my rootfs, it hangs at following message:
> >
> > RAMDISK: Compressed image found at block 0
> >
> > VFS: Mounted root (ext2 filesystem) readonly.
> >
> > Freeing unused kernel memory: 104k init
> >
> > EXT2-fs warning: checktime reached, running e2fsck is recommended
> >
> >
> >
> > I had add printk in tty_write() of drivers/char/tty_io.c, the message f=
rom
> > rootfs have printed.
> >
> > The conclusion is that message can be printed by printk() in linux kern=
el,
> > but can't be printed by printf() in user mode. I think it must be
> something
> > wrong for my UART configurations, does anybody know it??
> >
> >
> >
> >
> >
> > Best Regards,
> >
> > Johnson Cheng
> > _______________________________________________
> > Linuxppc-embedded mailing list
> > Linuxppc-embedded@ozlabs.org
> > https://ozlabs.org/mailman/listinfo/linuxppc-embedded
> >
> >
>=20
>=20
> --
> Daniel
> _______________________________________________
> Linuxppc-embedded mailing list
> Linuxppc-embedded@ozlabs.org
> https://ozlabs.org/mailman/listinfo/linuxppc-embedded
>=20
>=20


--=20
Daniel