Hello everyone,
I am experiencing a problem similar to the one described at https://dev.openwrt.org/ticket/6853 . I have a board based on the Ralink RT5350 chip, 32MB of RAM, 8MB of Flash and I am trying to use various 3G/4G modems with it. The kernel is 3.8.13, the firmware is based on https://github.com/kaechele/openwrt .
Some of the 3G modems are only detected if they are inserted _after_ the board is powered up. If they are already in the USB port at the time the board gets power, the system acts as if there is nothing inserted. A soft reboot doesn't fix it. Removing the 3G modem and re-inserting it makes it show up.
The modems that exhibit this behavior are:
Pantech UML295
Franklin U770
Novatel MC930D
Netgear 340U and 341U
The same problem also appears when using the standard Ralink firmware (using Ralink's 3.6.0 SDK, not OpenWRT) but only with the Netgear 340U and the 341U. The other 3 (Pantech UML295, Franklin U770 and Novatel MC930D) are detected fine.
I suspect it is some sort of timing issue. The Ralink firmware appears to put the USB port into power-saving mode (by setting UDEV_RST and UHST_RST to 1 in the RSTCTRL register, then turning off the associated clock by setting UPHY0_CLK_EN to 0) at boot time. The OpenWRT firmware appears to do something similar (the exact patch is this one: https://dev.openwrt.org/browser/trunk/t … ?rev=36260 ) but it appears to do so at a later time (when the USB port is enabled).
Has anyone else seen this before (on this particular chip or a similar one)? On this particular board there is no GPIO to turn off the power to the USB port, so if the power fails and the board + modem reboots, it will not be detected until someone physically unplugs the modem and plugs it back in.
Any suggestions would be greatly appreciated!
Thank you,
Razvan