ideas

[Jeroen Ruigrok/asmodai]

-On [20040723 09:02], Joerg Sonnenberger (joerg at xxxxxxxxxxxxxxxxx) wrote:
>I don't like it because there are still a lot of drives and chipsets out
>there which produce silent bit failures with ATAPI DMA enabled. But it might
>be possible to add it as option in the boot menu.

I am wondering how to detect this and add quirks for that.

For some background info:

"The RZ-1000 has two flaws. The CMD-640 has those same two flaws plus
three others. To make matters worse, most motherboard manufacturers
using these two flawed chips connected them up incorrectly. There are
software bypasses for these flaws. However, the Warp fix the CMD-640
reduces disk performance by 15 to 50%. The RZ-1000 fix has negligible
impact on disk I/O though it can slow down background processes.

When you are using an IDE or EIDE hard disk attached to the EIDE
motherboard port, the flaws subtly corrupt your files by randomly
changing bytes every once in a while. The flaws introduce bugs into
EXE files, subtle errors into your spreadsheets, stray characters into
your word processing documents, changes to the deductions in last
year's tax return files, and random changes to engineering design
files.

This corruption happens when you are simultaneously using your EIDE or
IDE hard disk and some other device, most commonly the floppy drive or
mag tape backup.

The same sorts of problem may occur on reading a CD-ROM drive attached
to an EIDE port.

PCI Motherboards (both 486 and Pentium) with the older Mercury and
Neptune chipsets are likely to have the flawed chips. The Mercury
chipset was popular in P60 and P66 systems, and the Neptune in P70,
P90 and P100 systems. Mercury chipsets are labelled with an MX suffix
and Neptune with NX. 

manufacturer: PC TECHNOLOGY INC
class code : 0001
Vendor ID: 1042
Device ID: 1000
Revision ID: 0001

manufacturer : CMD TECHNOLOGY INC
class code : 0001
Vendor ID :1095
Device ID : 0640
Revision ID : 0002

IBM Confirmed the RZ-1000 has two different flaws:

1)   In prefetch mode, multi-sector reads often fail.
2)   The chip erroneously responds to floppy status commands and
corrupts hard disk or CD-ROM I/O in the process.

IBM confirmed the CMD-640 has five different flaws:
1)   It has the same prefetch problem as the RZ-1000.
2)   It has the same floppy status problem as the RZ-1000.
3)   It does not support simultaneous I/O on the primary and secondary
EIDE ports.
4)   Confusion over legacy and PCI mode.
5)   Does not support 32-bit writes."

Another solution we might try is to enable DMA on DVD drives and on CD-R/W
drives.

Thus far I have seen reports about:

Western Digital WDC AC11000H, AC22100H, AC32500H, AC33100H, AC31600H - all
versions
Western Digital WDC AC32100H revision 24.09P07
Western Digital WDC AC23200L revision 21.10N21
Kenwood TrueX
samsung 32x cdrom drive model 3232 and a mitsumu cd-burner (2X)

DMA blacklist might be worthwhile to add within our driver model.

-- 
Jeroen Ruigrok van der Werven <asmodai(at)wxs.nl> / asmodai / kita no mono
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