Hi,
I have here a SATA<->IDE bridge based on a JM20330 connected to
what the old IDE driver reported like this:
| via82cxxx 0000:00:07.1: VIA vt82c686a (rev 22) IDE UDMA66
| via82cxxx 0000:00:07.1: IDE controller (0x1106:0x0571 rev 0x10)
At the other end, it's connected to a Seagate ST31500341AS
SATA harddisk (well, that's kinda redundant ... ;-).
Now, reading from the disk seems to work perfectly, but writing
(dding /dev/zero to the block device) causes DMA timeouts every
few hundred megabytes - in between the timeouts, though,
throughput seems to be ok (~ 20 MB/s).
Once the fallback mechanism has switched back to PIO4, things seem
to work perfectly, albeit slowly :-)
In the kernel log, the errors look something like this, with
small variations (at least to my eyes ;-):
| ata2.00: exception Emask 0x0 SAct 0x0 SErr 0x0 action 0x6 frozen
| ata2.00: failed command: WRITE DMA EXT
| ata2.00: cmd 35/00:00:67:19:4f/00:04:00:00:00/e0 tag 0 dma 524288 out
| res 40/00:00:00:00:00/00:00:00:00:00/00 Emask 0x4 (timeout)
| ata2.00: status: { DRDY }
| ata2: link is slow to respond, please be patient (ready=0)
| ata2: device not ready (errno=-16), forcing hardreset
| ata2: soft resetting link
| ata2.00: configured for UDMA/66
| ata2.00: device reported invalid CHS sector 0
| ata2: EH complete
That's all happening with a vanilla 2.6.33 (plus tuxonice, in case that
could have any effect on this). The legacy IDE drivers behave similarly.
So: Is there anything one could do about that, other than forcing
PIO-only operation? If you need any further information, please let
me know.
BTW, the datasheet of the JM20330 can be found at
http://www.mcuol.com/aspx/down.aspx?id=1266, just in case you didn't
know that yet ...
Florian
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