Albert Lee wrote:
Summary:
SiI 3611 is currently the only known chip that needs DMADIR.
Since SiI 3611 doesn't implement the ATA-7 word 62 or mangle identify
packet device data, it's hard to check the chip and turn on the DMADIR
support automatically. (Currently the libata DMADIR support can be
turned on manually by module parameter.)
Wonderful test report, thanks a _bunch_ for investigating this.
To turn on the DMADIR support automatically, maybe we can check whether
the ATAPI device is bridged (by ata_dev_knobble()). If bridged, we can
try to issue a ATAPI DMA read command to check if ATAPI DMA works.
If not work, then try turning on DMADIR or turn off ATAPI DMA.
Sounds like more complexity than its worth, for one non-spec-compliant
bridge chip. The module option gets the 3611 going, so IMO the current
level of support is adequate.
BTW, I found a 3611 here, and put it into my primary fileserver,
attaching to a DMA-capable PATA CD-RW drive.
Jeff
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