libata-core Disabling IRQ with new Compact Flash

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I went back to the NIOS II IDE and verified that this new CF has a controller problem, the interrupt IS NOT cleared when the status register is read. This goes against the ATA spec. We will be contacting the company.

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Hi jpe1313 and Kazuyasu,

as I understand the C-440 cards have following behaviour:

After 500ms host inactivity the card goes in idle mode to save energy.

In idle mode it does not clear the interrupt line, even if the status register is read.

The card wakes up from idle mode only by writing the command register.

In normal cases the host always starts with an idle command after a longer inactivity.

• could your problem be related to this inactivity time?

I investigated the behaviour of a Swissbit C-440 card at a standard mainboard with debug environment of DOS and recorded the trace:

https://www.alteraforum.com/forum/attachment.php?attachmentid=7317

After writing the command register with 0xEC

DASP down

PDIAG down

PDIA up

interrupt up

read status register (780µs after the command) -->0x58

interrupt down (56ns after rising iord-edge)

During this

IORDY, PDIAG-, IOCS16, RESET-, DMACK-, CS1, IOWR- high

DMARQ, DASP low

CS0 high, low before reading the status register

• what are the differences in your system?

• could you make a trace?

Marco