Hi. I initially started a thread on a different mailing list [1], and you can take look there for some additional background.
I am using a 4.14.15 stable kernel on a RK3288 SoC (FireFly RK3288 board) which uses the DW2 USB core. I have noticed that when connecting a USB device there is unreasonable high CPU load produced by the USB interrupts. Here is one example with a MIDI keyboard connected on USB (not really doing anything on it) 79 2 root SW 0 0% 19% [irq/45-dwc2_hso] 78 2 root SW 0 0% 11% [irq/45-ff540000] Can also see that there is a "HIGH" interrupt count root@esp5-d1:~# watch cat /proc/interrupts | grep usb 45: 43681938 0 0 0 GIC-0 57 Level ff540000.usb, dwc2_hsotg:usb1 46: 0 0 0 0 GIC-0 55 Level ff580000.usb, ff580000.usb, dwc2_hsotg:usb2 45: 43829473 0 0 0 GIC-0 57 Level ff540000.usb, dwc2_hsotg:usb1 46: 0 0 0 0 GIC-0 55 Level ff580000.usb, ff580000.usb, dwc2_hsotg:usb2 45: 43972333 0 0 0 GIC-0 57 Level ff540000.usb, dwc2_hsotg:usb1 46: 0 0 0 0 GIC-0 55 Level ff580000.usb, ff580000.usb, dwc2_hsotg:usb2 45: 44118769 0 0 0 GIC-0 57 Level ff540000.usb, dwc2_hsotg:usb1 46: 0 0 0 0 GIC-0 55 Level ff580000.usb, ff580000.usb, dwc2_hsotg:usb2 45: 44267876 0 0 0 GIC-0 57 Level ff540000.usb, dwc2_hsotg:usb1 46: 0 0 0 0 GIC-0 55 Level ff580000.usb, ff580000.usb, dwc2_hsotg:usb2 Again not really doing anything with the device, it is just connected. I have also tested with server different devices with same result (BT and WLAN). The CPU load is exposed when I add "threadirqs" to kernel arguments, otherwise it does not seem that it accounted for (not see in "top") but the number of interrupts is still high. Any thoughts on this? Please let me know if there is additional information that I can provide to help debug this. [1]. https://www.spinics.net/lists/linux-rt-users/msg18341.html -- Med Vänliga Hälsningar / Best Regards Mirza Krak -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
