[SCSI] isci: Fix interrupt coalescing assumption of active TCs (44ef2bf7) · Commits · 戴 / test

We always assign a dummy task context to a port in order to address a silicon issue. We have 4 ports per controller. So when idle, there are always exactly 4 TCs "active". The adaptive interrupt coalescing code uses number of active TCs to figure out the coalescing values. However, we never hit "0" TCs because of the 4 dummy TCs. Putting in fix so that we calculate this correctly. Reported-by:

Dan Melnic <dan@seamicro.com> Signed-off-by:

Dave Jiang <dave.jiang@intel.com> Signed-off-by:

James Bottomley <JBottomley@Parallels.com>

drivers/scsi/isci/host.c

+8 −2

Original line number	Original line	Diff line number	Diff line
	@@ -1122,10 +1122,16 @@ void isci_host_completion_routine(unsigned long data)
	sci_controller_completion_handler(ihost);		sci_controller_completion_handler(ihost);
	spin_unlock_irq(&ihost->scic_lock);		spin_unlock_irq(&ihost->scic_lock);

	/* the coalesence timeout doubles at each encoding step, so		/*
			* we subtract SCI_MAX_PORTS to account for the number of dummy TCs
			* issued for hardware issue workaround
			*/
			active = isci_tci_active(ihost) - SCI_MAX_PORTS;

			/*
			* the coalesence timeout doubles at each encoding step, so
	* update it based on the ilog2 value of the outstanding requests		* update it based on the ilog2 value of the outstanding requests
	*/		*/
	active = isci_tci_active(ihost);
	writel(SMU_ICC_GEN_VAL(NUMBER, active) \|		writel(SMU_ICC_GEN_VAL(NUMBER, active) \|
	SMU_ICC_GEN_VAL(TIMER, ISCI_COALESCE_BASE + ilog2(active)),		SMU_ICC_GEN_VAL(TIMER, ISCI_COALESCE_BASE + ilog2(active)),
	&ihost->smu_registers->interrupt_coalesce_control);		&ihost->smu_registers->interrupt_coalesce_control);

Admin message