Re: libata-dev#upstream pdc_adma fails IDENTIFY w/ AC_ERR_HSM

[Mark Lord <liml@rtr.ca>]

Jeff Garzik wrote:
> Tejun Heo wrote:
>> [adma_intr_mmio      ] ata1: protocol 2 (dev_stat 0x58)
>> [ata_port_flush_task ] ENTER
>> [ata_port_flush_task ] flush #1
>> ata1: ata_port_flush_task: flush #2
>> ata1: ata_port_flush_task: EXIT
>> ata1.00: failed to IDENTIFY (I/O error, err_mask=0x2)
> 
> 
> AC_ERR_HSM comes from the call to ac_err_mask().  Given a Status of 
> 0x58, it would appear that DRQ is asserted.
> 
> So if I had to guess, I would say that the above interrupt is the 
> DRQ-is-asserted indication, which would imply perhaps that this driver 
> should not bother with PIO polling.

I think this illustrates just how few people (Tejun) actually have
these chips and use them with Linux.  :)

I don't have a system to test this with today (long story),
but I'm trying to piece one together for later.

Is this "IDENTIFY using IRQs rather than polling" a newish feature?
Because I just don't see how it could work with the the existing
adma_intr_mmio routine --> that code is only correct for non-data
commands, and IDENTIFY definitely has data.

Borken driver, for sure.