Hi ,
We've implement i.MX6 Dual plus/Quad plus and Yocto 1.8 .
USB port of HOST/OTG are unstable at both Dual plus and Quad plus .
If we try to do "time dd if=/dev/sda1 of=/dev/null bs=8k" , then sometimes show the message as below
==> "usb 1-1: reset high-speed USB device number 2 using ci_hdrc" .
==> "Buffer I/O error on device sda1"
==> "usb 1-1: device firmware changed"
So we've measure the USB signals and power , the report as attached file looks fine .
Also we try to reduce USB trace length (under 1200mils) , but still can't fix this issue .
So
(1) Does it have any power rail for internal USB logic , we need to double confirm ?
(2) Do you have any suggestion about USB Test item (EL_xx) we need to check , if we'll measure Hi-Speed USB signals again ?
(3) Does it have any register cause these wrong message ? Could we try to disable it ?
(4) Other recommend ?
Thanks a lot.
Terry
Hi ,
I've change the value of address: 0x021b0400 to 0x14420000 from 0x514201f0 ,then it can fix this USB issue .
Address : 21B_0400 is MMDC Core AXI Reordering Control Register .
Thanks a lot.
Hi Terry
reason for instability may be VDD_VBUS_CAP -power rail for internal USB logic,
as well as DDR errors, so recommended to test it with ddr test:
i.MX6/7 DDR Stress Test Tool V2.52
AN4589 Configuring USB on i.MX 6 Series Processors
on p.7 shows setting for improving usb signals
http://cache.nxp.com/files/32bit/doc/app_note/AN4589.pdf
Also one can check sect.3.11 USB recommendations
i.MX6 System Development User’s Guide
http://cache.freescale.com/files/32bit/doc/user_guide/IMX6DQ6SDLHDG.pdf
Best regards
igor
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