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Hi,
I have a Cyclone V (kernel 4.1.22-ltsi-rt) with an USB3320 transceiver connected to USB1. There is a USB2422 HUB (2 port) connected to USB3320. One of the ports is connected to a 4 port CY7C65630.
CV <--> USB3320 <--> USB2422 <-port 2-> CY7C65630 <-4-ports-> (unused)
|
<-port 1-> USB Flash
When I plug-in a USB flash to USB2422 (port 1), CPU load increases by ~30% (two IRQ 36 handlers). I've found out that this is mainly due to the Start-of-Frame (SOF) interrupts being triggered every 125us. I have also enabled CONFIG_USB_DWC2_TRACK_MISSED_SOFS in the kernel and I get a dump of first 1000 missed SOFS very quickly. Except from the above, the USB Flash is mounted and can be used without a problem. My question is, is the CPU load normal or have I configured something incorrectly? usbphy0: usbphy@0 { # phy-cells = <0>; compatible = "usb-nop-xceiv"; status = "okay"; }; usb0: usb@ffb00000 { compatible = "snps,dwc2"; reg = <0xffb00000 0xffff>; interrupts = <0 125 4>; clocks = <&usb_mp_clk>; clock-names = "otg"; phys = <&usbphy0>; phy-names = "usb2-phy"; status = "disabled"; }; usb1: usb@ffb40000 { compatible = "snps,dwc2"; reg = <0xffb40000 0xffff>; interrupts = <0 128 4>; clocks = <&usb_mp_clk>; clock-names = "otg"; phys = <&usbphy0>; phy-names = "usb2-phy"; status = "disabled"; }; BR mrkozmic
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Dear Mr. @mrkozmic
Have you been able to fix this issue?
Like you, I'm currently testing a Cyclone V Board [1] with Linux Kernel 4.1.22 with RT Patch.
My USB Devices are a little different:
CV <--> USB3320 <--> SMSC_LAN9500
I don't have a hub connected to the USB-PHY. I am directly connecting an USB to Ethernet device.
I disabled the OTG, so that I only have two IRQs instead of the default 3 IRQs assigned by the dwc2 driver (USB driver).
I am currently watching around 20% CPU usage, but when I had the 3 interrupts, I also had 30% CPU usage exactly like you reported.
The number of interrupts observed on /proc/interrupts for IRQ45 (all USB interrupts) are also very very high too, around 7000 interrupts per second!
For debug, I also tested the non-RT version and this issue does not occur.
Best Regards,
Ventura
[1] - https://rocketboards.org/foswiki/Documentation/ArrowSoCKitEvaluationBoard
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Dear Mr. @mrkozmic and Ventura,
Did you get any conclusion on the above commented issue? We are experiencing the same situation in our Cyclone V based board.
Regards,
Mr Fdez
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