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<TITLE>Ask a technical problem happened on PPC board</TITLE>
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<P DIR=LTR><SPAN LANG="en-us"><FONT COLOR="#1F497D" FACE="Calibri">HI, all:</FONT></SPAN><SPAN LANG="en-us"></SPAN></P>
<P DIR=LTR ALIGN=JUSTIFY><SPAN LANG="en-us"></SPAN><SPAN LANG="en-us"></SPAN><SPAN LANG="en-us"><FONT FACE="Calibri"> </FONT> <FONT FACE="Calibri">Sorry to disturb all of you in the linuxppc-dev mail group. I am a new member from linuxppc-dev from China, and I have a very weird problem, it have been bothering me for a long time. I will be very grateful if you can help me to analyse it.</FONT></SPAN></P>
<P DIR=LTR ALIGN=JUSTIFY><SPAN LANG="en-us"><FONT FACE="Calibri"> 1) Problem</FONT> <FONT FACE="Calibri">description:</FONT></SPAN></P>
<P DIR=LTR ALIGN=JUSTIFY><SPAN LANG="en-us"><FONT FACE="Calibri">a) FRIU(a circuit board) unit is a ppc(powerpc) unit, 256 M bytes Ram, bootloader is uboot, kernel linux-2.6.21 filesystem: initramfs</FONT></SPAN></P>
<P DIR=LTR ALIGN=JUSTIFY><SPAN LANG="en-us"><FONT FACE="Calibri">The main problem is that when kernel start up and mount initramfs, run the init process(pid 1), when the proc</FONT><FONT FACE="Calibri">ess(init) write file(20 M bytes) to filesystem(initramfs),</FONT></SPAN></P>
<P DIR=LTR ALIGN=JUSTIFY><SPAN LANG="en-us"><FONT FACE="Calibri">sometimes it will find some data modified when check the file</FONT><FONT FACE="Calibri">’</FONT><FONT FACE="Calibri">s contents by read it. </FONT></SPAN></P>
<P DIR=LTR ALIGN=JUSTIFY><SPAN LANG="en-us"><FONT FACE="Calibri">b) I have write a test init process which will write 20 Mbytes data(0xFF) to "/TEST0.IMG" and check it's conten</FONT><FONT FACE="Calibri">ts. Sometimes, the contents will by modified.</FONT></SPAN></P>
<P DIR=LTR ALIGN=JUSTIFY><SPAN LANG="en-us"><FONT FACE="Calibri">c) Here is the test procedure: </FONT></SPAN></P>
<P DIR=LTR ALIGN=JUSTIFY><SPAN LANG="en-us"><FONT FACE="Calibri">Uboot download linux kernel and initramfs --> cmd "bootm" to start linux --></FONT></SPAN><SPAN LANG="en-us"></SPAN><SPAN LANG="en-us"> <FONT COLOR="#FF0000" FACE="Calibri">after kernel start complete, mount initramfs, run init process(pid 1)</FONT></SPAN></P>
<P DIR=LTR ALIGN=JUSTIFY><SPAN LANG="en-us"></SPAN><SPAN LANG="en-us"><FONT FACE="Calibri">--> It will write 20 Mbytes dat</FONT><FONT FACE="Calibri">a(0XFF) to 'TEST0.IMG' and check it's contents, If there is error, the error data will be printed.</FONT></SPAN></P>
<P DIR=LTR ALIGN=JUSTIFY><SPAN LANG="en-us"><FONT FACE="Calibri">2) Error data:</FONT></SPAN></P>
<P DIR=LTR ALIGN=JUSTIFY><SPAN LANG="en-us"><FONT FACE="Calibri">a) Every time the error happened, a pair of data modified:</FONT></SPAN></P>
<P DIR=LTR ALIGN=JUSTIFY><SPAN LANG="en-us"><FONT FACE="Calibri">first place: </FONT></SPAN><SPAN LANG="en-us"></SPAN><SPAN LANG="en-us"> <FONT COLOR="#FF0000" FACE="Calibri">1C 00 FF FF FF FF FF FF 00 00 00 040 80 ..</FONT></SPAN><SPAN LANG="en-us"></SPAN><SPAN LANG="en-us">.</SPAN></P>
<P DIR=LTR ALIGN=JUSTIFY><SPAN LANG="en-us"><FONT FACE="Calibri">Second place:</FONT></SPAN><SPAN LANG="en-us"></SPAN><SPAN LANG="en-us"> <FONT COLOR="#FF0000" FACE="Calibri">FF FF FF F</FONT><FONT COLOR="#FF0000" FACE="Calibri">F FF FF 00 A0 ....</FONT></SPAN><SPAN LANG="en-us"></SPAN><SPAN LANG="en-us"></SPAN></P>
<P DIR=LTR ALIGN=JUSTIFY><SPAN LANG="en-us"><FONT FACE="Calibri">Sometimes, there will be 2 pair of data modified.</FONT></SPAN></P>
<P DIR=LTR ALIGN=JUSTIFY><SPAN LANG="en-us"><FONT FACE="Calibri">b) The error happens not very often, but it happens sometime.</FONT></SPAN></P>
<P DIR=LTR ALIGN=JUSTIFY><SPAN LANG="en-us"><FONT FACE="Calibri">3)</FONT></SPAN></P>
<P DIR=LTR ALIGN=JUSTIFY><SPAN LANG="en-us"><FONT FACE="Calibri">Could you give me some advice on how to investigate it or which part you think will have problem? </FONT></SPAN></P>
<P DIR=LTR ALIGN=JUSTIFY><SPAN LANG="en-us"><FONT FACE="Calibri">Thanks very much!</FONT></SPAN></P>
<P DIR=LTR ALIGN=JUSTIFY><SPAN LANG="en-us"><FONT FACE="Calibri">Used</FONT><FONT FACE="Calibri"> kernel: linux-2.6.21</FONT></SPAN><SPAN LANG="en-us"></SPAN><SPAN LANG="en-us"></SPAN><SPAN LANG="en-us"><FONT FACE="SimSun" SIZE=2 COLOR="#000000"> <<init process write_read file(20Mbytes) error2.txt>> </FONT></SPAN><SPAN LANG="en-us"></SPAN><SPAN LANG="en-us"></SPAN><SPAN LANG="en-us"></SPAN><SPAN LANG="en-us"></SPAN><SPAN LANG="en-us"><FONT FACE="SimSun" SIZE=2 COLOR="#000000"> <<init process write_read file(20Mbytes) error.txt>> </FONT></SPAN><SPAN LANG="en-us"></SPAN><SPAN LANG="en-us"></SPAN><SPAN LANG="en-us"></SPAN></P>
<P DIR=LTR ALIGN=JUSTIFY><SPAN LANG="en-us"><FONT FACE="Calibri">Br,</FONT></SPAN></P>
<P DIR=LTR ALIGN=JUSTIFY><SPAN LANG="en-us"><FONT FACE="Calibri">Wang Junhua</FONT></SPAN></P>
<P DIR=LTR ALIGN=JUSTIFY><SPAN LANG="en-us"></SPAN></P>
<P DIR=LTR><SPAN LANG="en-us"><B></B></SPAN><SPAN LANG="en-us"><B></B></SPAN><B><SPAN LANG="en-us"></SPAN><SPAN LANG="en-us"><FONT COLOR="#808080" FACE="Arial Black">Wang Junhua (Jonny)</FONT></SPAN></B><SPAN LANG="en-us"><I></I></SPAN><SPAN LANG="en-us"><I></I></SPAN><I><SPAN LANG="en-us"></SPAN></I></P>
<P DIR=LTR><I><SPAN LANG="en-us"><FONT COLOR="#808080" FACE="Arial">-----------------------------------------</FONT></SPAN></I></P>
<P DIR=LTR><I><SPAN LANG="en-us"><FONT COLOR="#808080" FACE="Arial">LINDX</FONT></SPAN></I></P>
<P DIR=LTR><I><SPAN LANG="en-us"><FONT COLOR="#808080" FACE="Arial">DX 200 R&D HZ Area E </FONT></SPAN></I></P>
<P DIR=LTR><I><SPAN LANG="en-us"><FONT COLOR="#808080" FACE="Arial">MP: +8615967154143</FONT></SPAN></I></P>
<P DIR=LTR><I><SPAN LANG="en-us"><FONT COLOR="#808080" FACE="Arial">Seat:4076</FONT></SPAN></I><SPAN LANG="en-us"></SPAN><SPAN LANG="en-us"></SPAN><SPAN LANG="en-us"></SPAN></P>
<P DIR=LTR ALIGN=JUSTIFY><SPAN LANG="en-us"></SPAN></P>
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