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| author | Dave Jiang <dave.jiang@intel.com> | 2012-09-05 16:35:44 -0700 |
|---|---|---|
| committer | James Bottomley <JBottomley@Parallels.com> | 2012-09-24 12:11:04 +0400 |
| commit | 44ef2bf72df34ef2628dc3475b4507ab984d6744 (patch) | |
| tree | 39181c92c6f2bd9d9dffa4dac9a287e16280307c /drivers/scsi/isci | |
| parent | 54b46677757ff8d6c282305fc7710f466b63d6dc (diff) | |
| download | kernel-common-44ef2bf72df34ef2628dc3475b4507ab984d6744.tar.gz kernel-common-44ef2bf72df34ef2628dc3475b4507ab984d6744.tar.bz2 kernel-common-44ef2bf72df34ef2628dc3475b4507ab984d6744.zip | |
[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: Dan Melnic <dan@seamicro.com>
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Signed-off-by: James Bottomley <JBottomley@Parallels.com>
Diffstat (limited to 'drivers/scsi/isci')
| -rw-r--r-- | drivers/scsi/isci/host.c | 10 |
1 files changed, 8 insertions, 2 deletions
diff --git a/drivers/scsi/isci/host.c b/drivers/scsi/isci/host.c index d4daa0f24595..ab026a50ace3 100644 --- a/drivers/scsi/isci/host.c +++ b/drivers/scsi/isci/host.c @@ -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); |