Serieal console on Samsung S3C6410 ARM11 CPU (Was [ANNOUNCE] 3.0.6-rt17)

Serieal console on Samsung S3C6410 ARM11 CPU (Was [ANNOUNCE] 3.0.6-rt17)

[Thomas Abraham]

Hi Juergen,

On 8 October 2011 16:56, Juergen Beisert <jbe@pengutronix.de> wrote:
> Thomas Gleixner wrote:
>> I'm pleased to announce the 3.0.6-rt17 release.
>
> I have no idea where to search, but when I'm using the 3.0.6-rt17 on my
> Samsung S3C6410 ARM based system, the UART (serial console) does not work as
> expected. Typing only one char at a time is okay. Typing two chars
> immediately makes the system using 100 % CPU load and takes about 2 seconds
> to respond. It seems the interrupt handling is broken in the UART driver, but
> I don't know how to fix it.
>
> This with a simple cursor up (one char to get the last command) and a small
> pause to the next "ENTER" char:
>
> root at mini6410:~ cat /proc/interrupts | grep 18:
> ?18: ? ?5739107 ?s3c-uart ?s3c6400-uart
>
> Same again:
>
> root at mini6410:~ cat /proc/interrupts | grep 18:
> ?18: ? ?5739113 ?s3c-uart ?s3c6400-uart
>
> 6 interrupts seems reasonable.
>
> Now with cursor up and SPACE immediately, then a pause for ENTER:
>
> root at mini6410:~ cat /proc/interrupts | grep 18:
> ?18: ? ?5923815 ?s3c-uart ?s3c6400-uart
>
> 184702 interrupts looks strange.

Just curious, do you have the following two commits?

serial: samsung: Add unified interrupt handler for s3c64xx and later SoC's
ARM: SAMSUNG: Remove uart irq handling from platform code

Thanks,
Thomas.

Serieal console on Samsung S3C6410 ARM11 CPU (Was [ANNOUNCE] 3.0.6-rt17)

[Juergen Beisert]

Hi Thomas,

Thomas Abraham wrote:
> On 8 October 2011 16:56, Juergen Beisert <jbe@pengutronix.de> wrote:
> > Thomas Gleixner wrote:
> >> I'm pleased to announce the 3.0.6-rt17 release.
> >
> > I have no idea where to search, but when I'm using the 3.0.6-rt17 on my
> > Samsung S3C6410 ARM based system, the UART (serial console) does not work
> > as expected. Typing only one char at a time is okay. Typing two chars
> > immediately makes the system using 100 % CPU load and takes about 2
> > seconds to respond. It seems the interrupt handling is broken in the UART
> > driver, but I don't know how to fix it.
> >
> > This with a simple cursor up (one char to get the last command) and a
> > small pause to the next "ENTER" char:
> >
> > root at mini6410:~ cat /proc/interrupts | grep 18:
> > ?18: ? ?5739107 ?s3c-uart ?s3c6400-uart
> >
> > Same again:
> >
> > root at mini6410:~ cat /proc/interrupts | grep 18:
> > ?18: ? ?5739113 ?s3c-uart ?s3c6400-uart
> >
> > 6 interrupts seems reasonable.
> >
> > Now with cursor up and SPACE immediately, then a pause for ENTER:
> >
> > root at mini6410:~ cat /proc/interrupts | grep 18:
> > ?18: ? ?5923815 ?s3c-uart ?s3c6400-uart
> >
> > 184702 interrupts looks strange.
>
> Just curious, do you have the following two commits?
>
> serial: samsung: Add unified interrupt handler for s3c64xx and later SoC's
> ARM: SAMSUNG: Remove uart irq handling from platform code

Are they part of the current 3.0.6 vanilla kernel? I'm only using the vanilla 
3.0.6 with rt17 on my target.

jbe

-- 
Pengutronix e.K.                              | Juergen Beisert             |
Linux Solutions for Science and Industry      | http://www.pengutronix.de/  |

Serieal console on Samsung S3C6410 ARM11 CPU (Was [ANNOUNCE] 3.0.6-rt17)

[Thomas Abraham]

On 8 October 2011 23:45, Juergen Beisert <jbe@pengutronix.de> wrote:
> Hi Thomas,
>
> Thomas Abraham wrote:
>> On 8 October 2011 16:56, Juergen Beisert <jbe@pengutronix.de> wrote:
>> > Thomas Gleixner wrote:
>> >> I'm pleased to announce the 3.0.6-rt17 release.
>> >
>> > I have no idea where to search, but when I'm using the 3.0.6-rt17 on my
>> > Samsung S3C6410 ARM based system, the UART (serial console) does not work
>> > as expected. Typing only one char at a time is okay. Typing two chars
>> > immediately makes the system using 100 % CPU load and takes about 2
>> > seconds to respond. It seems the interrupt handling is broken in the UART
>> > driver, but I don't know how to fix it.
>> >
>> > This with a simple cursor up (one char to get the last command) and a
>> > small pause to the next "ENTER" char:
>> >
>> > root at mini6410:~ cat /proc/interrupts | grep 18:
>> > ?18: ? ?5739107 ?s3c-uart ?s3c6400-uart
>> >
>> > Same again:
>> >
>> > root at mini6410:~ cat /proc/interrupts | grep 18:
>> > ?18: ? ?5739113 ?s3c-uart ?s3c6400-uart
>> >
>> > 6 interrupts seems reasonable.
>> >
>> > Now with cursor up and SPACE immediately, then a pause for ENTER:
>> >
>> > root at mini6410:~ cat /proc/interrupts | grep 18:
>> > ?18: ? ?5923815 ?s3c-uart ?s3c6400-uart
>> >
>> > 184702 interrupts looks strange.
>>
>> Just curious, do you have the following two commits?
>>
>> serial: samsung: Add unified interrupt handler for s3c64xx and later SoC's
>> ARM: SAMSUNG: Remove uart irq handling from platform code
>
> Are they part of the current 3.0.6 vanilla kernel? I'm only using the vanilla
> 3.0.6 with rt17 on my target.

No. I don't think they are part of 3.0.6 kernel. I am not sure of the
issue you have with serial console, but if you do not have these
patches already applied, you could try with them.

Thanks,
Thomas.