Tejun,
On 1/21/11, Tejun Heo <tj@xxxxxxxxxx> wrote:
> On Fri, Jan 21, 2011 at 05:29:39PM +0530, viresh kumar wrote:
>> sda: unknown partition table
>
> and then this probably is unrelated. So, no IO error is being
> reported but the above still fails? How did you verify the read data
> are actually the same? Maybe there's a cache alias issue?
>
This issue is solved now and was related to cache only. As i mentioned earlier
Arasan CF controller doesn't xfer data from/to RAM. And so i was using CPU
to copy data. After data is passed to libata, in page_unmap, cache was
getting invalidated.
And so data written by CPU is lost.
Now i am using external DMA controller to copy data to CF FIFO, and am able to
read/write data to CF card.
But i am facing another issue now. I am getting following error
sometimes, when i
copy > 10 MB of data to CF card.
ata1.00: exception Emask 0x0 SAct 0x0 SErr 0x0 action 0x6 frozen
ata1.00: BMDMA stat 0x5
ata1.00: failed command: WRITE DMA
ata1.00: cmd ca/00:00:3f:7f:3c/00:00:00:00:00/e0 tag 0 dma 131072 out
res d0/00:00:3f:7f:3c/00:00:00:00:00/e0 Emask 0x2 (HSM violation)
ata1.00: status: { Busy }
I debugged it further and found that after data is transferred,
altstatus register is
returning status 0xd0, which means ATA_BUSY.
I am not sure why this must be returned by card after data is transferred?
--
viresh
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