From: Shanyu Zhao <shanyu.zhao@xxxxxxxxx> Previously in interrupt handling tasklet, iwlwifi driver only clear/ack those interrupts that are enabled by the driver through inta_mask. If the hardware generates unattended interrupts, driver will not ack them, defeating the interrupt coalescing feature. This results in high number of interrupts per second and high CPU utilization. This patch addresses this issue by acking those unattended interrupts in the tasklet. Local test showed an order of magnitude improvement in terms of the number of interrupts without sacrificing networking throughput. This is a workaround for hardware issue. Signed-off-by: Shanyu Zhao <shanyu.zhao@xxxxxxxxx> Signed-off-by: Zhu Yi <yi.zhu@xxxxxxxxx> Signed-off-by: Reinette Chatre <reinette.chatre@xxxxxxxxx> --- drivers/net/wireless/iwlwifi/iwl-agn.c | 10 +++++++++- 1 files changed, 9 insertions(+), 1 deletions(-) diff --git a/drivers/net/wireless/iwlwifi/iwl-agn.c b/drivers/net/wireless/iwlwifi/iwl-agn.c index c8e2e3a..e4c2e1e 100644 --- a/drivers/net/wireless/iwlwifi/iwl-agn.c +++ b/drivers/net/wireless/iwlwifi/iwl-agn.c @@ -1258,7 +1258,15 @@ static void iwl_irq_tasklet(struct iwl_priv *priv) /* Ack/clear/reset pending uCode interrupts. * Note: Some bits in CSR_INT are "OR" of bits in CSR_FH_INT_STATUS, */ - iwl_write32(priv, CSR_INT, priv->inta); + /* There is a hardware bug in the interrupt mask function that some + * interrupts (i.e. CSR_INT_BIT_SCD) can still be generated even if + * they are disabled in the CSR_INT_MASK register. Furthermore the + * ICT interrupt handling mechanism has another bug that might cause + * these unmasked interrupts fail to be detected. We workaround the + * hardware bugs here by ACKing all the possible interrupts so that + * interrupt coalescing can still be achieved. + */ + iwl_write32(priv, CSR_INT, priv->inta | ~priv->inta_mask); inta = priv->inta; -- 1.6.3.3 -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
