Alan Cox wrote:
On Mon, 19 Mar 2007 13:42:37 +0900
Tejun Heo <htejun@xxxxxxxxx> wrote:
Tony Vroon wrote:
This duplicates the IDE core LED trigger in the libata core.
I plan to use this by allowing PMU LED control on G5 towers. My test platform
is a PowerMac 7,3 (Dual G5 2.0GHz, June 2004) with a K2 (sata_svw) controller.
I think this fits better in libata-core.c::ata_qc_issue(). Can you move
it to there?
Gak. I'd rather it stayed out of ata_qc_issue() which is a critical path
for performance.
The original place is in the critical path too. It's just at the outer
function which eventually calls ata_qc_issue() (the mapping is almost
one to one).
Our command issu is already too heavy and not all
controllers have queueing to absorb that. How many controllers actually
need this hook and can we not have ata_qc_issue_with_led() helpers for
them ?
Our issue path is somewhat expensive due to SCSI -> ATA translation but
I don't think it really matters on any modern cpu. It can definitely
hurt on embedded tho. :-(
--
tejun
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