Re: PROBLEM: kernel 2.6.22.6 pata_pdc202xx_old.c limiting to UDMA/33 instead of UDMA/100 (UPDATED 2.6.22.6)

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To: n <xellos@...>
Cc: Alan Cox <alan@...>, <linux-ide@...>, <linux-kernel@...>
Date: Saturday, September 1, 2007 - 10:58 am

Dear n:

    Please do *not* follow-up to a completely inderended thread. Start your 
own, please. :-/


    Gathering courage and reply to libata bug report -- I'm more of the 
drivers/ide/ guy with some SCSI background too... :-)



    That was an attempt to read 1 sector from LBA 0xfc9c25 of rhe drive #1...


     Whee! :-)


[...]

    RTL8139 are PoS chips (unless it's 8139D probably)... :-)


     Hmmm, I'd assume that after that DMA wouldn't be possible but...



    That was an attempt to read the 1st sector from LBA 0x3f of the drive...


    ... which failed miserably, with UltraDMA CRC error. Hmmm...


     ... same sh!t happened again at UDNA/33 presumbly...


    But the DMA write failed again with the same CRC error...


    ... and again.


    ... and again, even with UDMA 25.


    Bug is quite persistent... something's up!


    Yeah, 63 == 0x3f.


    Thrying to DMA write 0 sectors at 0xc9c25.


    Hm, 0x40 is not normal a status value... usually, it's 0x50.  But it's 
alright anyway.


    Hm...


    Same here.


    Again strange status after writinng 0 sectors the same LBA.

[The same us repeating over and over again...]


    Hm, never seen sense format 0x72... :-)
    The 2nd byte is prolly a sense key ABORTED COMMAND?


   Aha, 0x3f again, this time in the SCSI sense... I've looked thru the SCSI 
spacs and found nought aboutthis format. :-(


    Then everything happily continues in the same vein but t UDMA/25 mode.
[...]



     Probably host side detecton is borked. The drived is residing alone on 
that cable?


   Hrm, then maybe it's indeed device side problem (but IIRC, libata used to 
ignore device side reporting)./



    Hardly so...


    Not on the same cable?


    Write of single sector 63 fails miserably with UltraDMA CRC... although, 
if you're not using UltraDMA at this moment, 0x84 may mean something 
different: bad/uncortrectable sector.


    Hmmm, the driver had just lied to you saying that it downgraded to PIO4 -- 
it still issues WRITE DMA command which failed as usual...


    "Then it strted all over again..."


    Hh, SCSI msgs cleared the forat up for me: byte 1 is a sense key, byte 2 
is ASQ (0x47 means SCSI parity error)...


    Again failinig DMA write of 0 sectors at LBA 826401...


   It means that IDE DMA has signalled an interrupt


    Aha, those last 4 bytes a big-endian address of a requested LBA to write to


    From looking at the logs I got a feeling that the speed downgraded didn't 
work all the way to PIO...


    Aha, thanks! :-)



    Yeah, all that is very confusing...

MBR, Sergei
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Re: PROBLEM: kernel 2.6.22.6 pata_pdc202xx_old.c limiting to..., Sergei Shtylyov, (Sat Sep 1, 10:58 am)