On Thu, 24 Sep 2009, Anton Vorontsov wrote:

Though, there are few other issues with suspend/resume in this driver.
The intention of calling free_irq() in suspend() was to avoid any
possible spurious interrupts (see commit 5b039e681b8c5f30aac9cc04385
"3c59x PM fixes"). But,

- On resume, the driver was requesting IRQ just after pci_set_master(),
  but before vortex_up() (which actually resets 3c59x chips).

Shouldn't it be possible to reset the chip (or at least prevent it from 
generating spurious IRQs) during the early-resume phase?

- Issuing free_irq() on a shared IRQ doesn't guarantee that a buggy
  HW won't trigger spurious interrupts in another driver that
  requested the same interrupt. So, if we want to protect from
  unexpected interrupts, then on suspend we should issue disable_irq(),
  not free_irq().

What if some other device shares the IRQ and still relies on receiving
interrupts when this code runs?  Won't disable_irq() mess up the other
device?

Alan Stern