Hello, I have stranhe behaviour in which even when there is no activity in serial port, the retention counter is keep incremented all these time, as if the cpu gets in and out of retention periodically. I would expect the cpu to get into retention mode, when there is no activity and stay in that state. What can cause such behaviour ? Is it because some background process ? These are the processes I see using ps command : ~ # ps PID USER VSZ STAT COMMAND 1 root 2088 S init 2 root 0 SW [kthreadd] 3 root 0 SW [ksoftirqd/0] 4 root 0 SW [kworker/0:0] 5 root 0 SW [kworker/u:0] 6 root 0 SW< [khelper] 7 root 0 SW [irq/72-serial i] 8 root 0 SW [irq/73-serial i] 9 root 0 SW [irq/74-serial i] 10 root 0 SW [sync_supers] 11 root 0 SW [bdi-default] 12 root 0 SW< [kblockd] 13 root 0 SW [khubd] 14 root 0 SW [kseriod] 15 root 0 SW< [twl4030-irqchip] 16 root 0 SW [twl4030-irq] 17 root 0 SW [irq/378-twl4030] 18 root 0 SW [kworker/u:1] 19 root 0 SW< [musb-hdrc.0] 20 root 0 SW< [kconservative] 21 root 0 SW [kswapd0] 22 root 0 SW< [aio] 23 root 0 SW< [crypto] 29 root 0 SW [mtdblock0] 30 root 0 SW [mtdblock1] 31 root 0 SW [mtdblock2] 32 root 0 SW [mtdblock3] 33 root 0 SW [mtdblock4] 34 root 0 SW [mtdblock5] 35 root 0 SW [mtdblock6] 36 root 0 SW [mtdblock7] 37 root 0 SW [mtdblock8] 38 root 0 SW [mtdblock9] 41 root 0 SW [kworker/0:1] 42 root 0 SW< [kondemand] 43 root 0 SWN [jffs2_gcd_mtd5] 46 root 0 SWN [jffs2_gcd_mtd6] 47 root 0 SWN [jffs2_gcd_mtd8] 48 root 0 SWN [jffs2_gcd_mtd7] 71 root 2364 S /usr/sbin/inetd 74 root 2092 S -/bin/sh 93 root 2092 R ps ~ # My original problem is that the ethernet performance is very low with small windows. I thought that I can control this value by changing sleep_latency parameter in the following array. Yet, it did not help me. I don't know why. static struct cpuidle_params cpuidle_params_table[] = { /* C1 */ {0, 2, 2, 5}, <-- changed valid to 0 (I am interested in getting into deepest state) /* C2 */ {0, 10, 10, 30}, <-- changed valid to 0 (I am interested in getting into deepest state) /* C3 */ {0, 50 , 50, 300}, <-- changed valid to 0 (I am interested in getting into deepest state) /* C4 */ {1, 1500000 , 1800, 4000}, <-- changed sleep_latency to 1500000 .... } Best Regards, Ran -- To unsubscribe from this list: send the line "unsubscribe linux-omap" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html