Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 44ef2bf7 authored by Dave Jiang's avatar Dave Jiang Committed by James Bottomley
Browse files

[SCSI] isci: Fix interrupt coalescing assumption of active TCs 



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: default avatarDan Melnic <dan@seamicro.com>
Signed-off-by: default avatarDave Jiang <dave.jiang@intel.com>
Signed-off-by: default avatarJames Bottomley <JBottomley@Parallels.com>
parent 54b46677

drivers/scsi/isci/host.c

+8 −2
Original line number Diff line number Diff line
@@ -1122,10 +1122,16 @@ void isci_host_completion_routine(unsigned long data) 
	sci_controller_completion_handler(ihost);

	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

	 */

	active = isci_tci_active(ihost);

	writel(SMU_ICC_GEN_VAL(NUMBER, active) |

	       SMU_ICC_GEN_VAL(TIMER, ISCI_COALESCE_BASE + ilog2(active)),

	       &ihost->smu_registers->interrupt_coalesce_control);