Messages in this thread | | | Date | Tue, 06 Sep 2005 22:01:40 -0400 | From | Jeff Garzik <> | Subject | Re: [PATCH 2.6.13] libata: use common pci remove in ahci |
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Brett Russ wrote: > Jeff Garzik wrote: >> Brett Russ wrote: >>> 2) Isn't it wrong for the IRQ disable at the chip to occur *after* >>> free_irq() is called to disconnect the handler (independent of >>> question 1...since this is the case currently)? Granted, all of the >>> ports have gone through scsi_remove_host() but theoretically there >>> still is a possibility the chip could interrupt.
Answer: depends on hardware.
For all hardware, the conditions that generate interrupts should be shut down, and then free_irq() is called after that.
Some hardware only needs per-port disable, or nothing besides clearing any commands, to ensure that interrupts from that hardware are disabled (this excludes shared interrupts, of course).
This logic is another reason why a driver author may choose to implement their own PCI ->remove() hook, rather than using the generic ata_pci_remove_one(). Eliminates the need for a ->host_stop() hook implementation, and allows one to perform tasks before calling free_irq(), as well as tasks after the call (normal ->host_stop stuff).
Jeff
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