I suspect that Albert will not be able to reply for a few days, there 
seems to be an issue with the weather in Taiwan, as in, they may be 
hunkered down for a typhoon.

On Fri, 05 Aug 2005 01:39:57 +0800, Albert Lee wrote:
>Jeff,
>
>Patch 3/3: Fix pdc2027x ATAPI DMA lost irq problem
>
>Description:
>   Sometimes pdc2027x will lost irq after ATAPI DMA data transfer.
>   With the previous rule (cmd->request_bufflen % 256), the ATAPI DMA irq lost
>problem still occurs during the test.

Do you want to lash up the analyzer here in Austin?  I suspect this may be 
a manifestation of a READ CAPACITY issue.  It is legal for the device fw 
to report the lead-in, and lead-out blocks in the total, but you cannot 
actually access the blocks from the device.  The blocks reported by 
READ CAPACITY can be off by 3 to the high side.

>
>   Root cause for the irq lost is unknown. I've tried your ATAPI DMA alignment
>patch, but the problem still occurs, even the buffer is aligned. I guess it is 
>pdc2027x hardware problem.
>
>   The following workarounds are adapted from the Promise pdc618 GPL driver.
>They seems know about the problem and has the workaround.
>
>Changes:
>   - Only turn on ATAPI DMA for READ, WRITE, READ_CD and READ_DVD_STRUCTURE 
> commands.
>   - For WRITE_10, if LBA -45150 (FFFF4FA2h) to  -1 (FFFFFFFFh) then use PIO 
> mode.
>

See above.

++doug

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