Re: [PATCH 2.6.19 2/3] sata_promise: new EH conversion

[Tejun Heo <htejun@gmail.com>]

Mikael Pettersson wrote:
>> Don't freeze port unconditionally.  You'll end up hardresetting on every
>> error.  Just make sure DMA engine is stopped and the controller is in a
>> sane state.  If that fails, then, the port should be frozen.

Sorry, s/hardresetting/resetting/

> I'm looking into this now, but so far it seems only a reset
> (what Promise calls software reset, I don't know if libata
> considers it a soft or hard reset) of the ATA channel will do.

Errors properly reported by the device shouldn't cause resets.  Think
about ATAPI check condition.

>>> +	hardreset = NULL;
>>> +	if (sata_scr_valid(ap)) {
>>> +		ehc->i.action |= ATA_EH_HARDRESET;
>> Why always force HARDRESET?
> 
> I based that on sata_sil24:
> 
> 	if (sil24_init_port(ap)) {
> 		ata_eh_freeze_port(ap);
> 		ehc->i.action |= ATA_EH_HARDRESET;
> 	}
> 
> I interpreted the ATA_EH_HARDRESET as being required due to
> the ata_eh_freeze_port(), but perhaps it's only there because
> sil24_init_port() returned failure?

Yeap, that's right.

> A different issue, but of practical importance, is which
> libata branch I should base the EH conversion on: #upstream
> or #ALL? Andrew Morton's -mm kernels include the ALL patches,
> but they in turn include the promise-sata-pata patches, and
> there is a conflict between the PATA patch and the EH conversion.
> Currently my EH conversion is based on #upstream, and I've ported
> the PATA patch to apply on top of it.

#upstream, It is.  #ALL is merge of all libata-dev devel branches and no
development work occurs there directly.

Thanks.

-- 
tejun