[PATCH V2] workaround for mpc52xx erratum #364 (serial may not be reset in break state)

[René Bürgel]

Matt Sealey schrieb:
>
>
> René Bürgel wrote:
>> But as the serial driver is also used for the MPC5121, we may have to 
>> distinguish anyway. Does anyone have the possibility to test if the 
>> bug in still present  on MPC5121?
>
> Tell us what to do to get it to occur and what we're looking for and we
> have a bunch of boards at Genesi, someone will find the time to test it
> (if not them, then me :)
>
> Right now I'm having a hell of a time getting a 2.6.27.x kernel running
> on it though, some driver support is still missing from mainline making
> it just that little bit extra frustrating to work with.. (if you're
> using the system over a serial console, how are you supposed to test
> serial port operation? USB doesn't work in >2.6.24 so I guess I have to
> hope netconsole works :)
>
Hi, Matt

Thanks for your offer. I'm using telnet to debug the serial port.  I'll 
append a testcase for you, which is just opening a serial port, trying 
to receive for a second, switching the baudrate and doing it receiving 
again. Just run it and connect a slow device to the serial port sending 
data continuously. I'm using a GPS mouse here, working at 9600baud. The 
higher the rate you are receiving at, the higher the chance to falsely 
receive a break. When the serial port is switch off in that moment (the 
filedescriptor is closed), the serial won't receive anything from that 
time, if the bug is present

Alternativly, if you have more control over your serial device, just 
send breaks continuously, open and close the serial port. Open it again 
and receiving data fails, if the bug is present.

Just btw: if USB is not working, did you miss the initialisation of the 
USB-controller in your bootloader? I had similar problems getting from 
2.6.22 to 2.6.25 with my mpc5200.

-- 
René Bürgel
Software Engineer
Unicontrol Systemtechnik GmbH
OT Dittersbach
Sachsenburger Weg 34
09669 Frankenberg
 
Tel.: 03 72 06/ 88 73 - 19
Fax: 03 72 06/ 88 73 - 60
E-Mail: r.buergel at unicontrol.de
Internet: www.unicontrol.de
 
Unicontrol Systemtechnik GmbH
Geschäftsführer: Dipl.-Ing. Siegfried Heinze
Sitz der Gesellschaft: Frankenberg
Registergericht: Amtsgericht Chemnitz, HRB 15 475

-------------- next part --------------
An embedded and charset-unspecified text was scrubbed...
Name: erratum364-tc.c
URL: <http://lists.ozlabs.org/pipermail/linuxppc-dev/attachments/20081106/0ad9f003/attachment.asc>