On Fri, Jul 25, 2014 at 10:02:15AM -0400, Alan Stern wrote: > On Thu, 24 Jul 2014, Michael Welling wrote: > > > So I may be barking up the wrong tree on this one. > > > > Today I discovered something that may lead to the resolution of my issue. > > > > The hardware I am using incorporates a USB switch on-board to avoid the > > having an external switch to plug in keyboards etc. If two devices are plugged > > into the downstream ports they are both detected on boot. When I unplug > > one of the devices and plug it back in, it is detected again. > > > > As long as one downstream device ports is populated the device discovery works > > on the other. Any clue on this? > > > > This reminded of a note that I made on the schematic after talking to SMSC. > > > > Set "UseExternalVbus Indicator" BIT 7 in register 0x0a. > > > > This is a PHY register that may actually be accessible in > > drivers/usb/phy/phy-ulpi.c > > but it looks like I cannot access the code from device tree. > > > > What would be the best way to go about adding support for this? > > Maybe you would learn more if you enabled USB debugging in your kernel. > Or if you used usbmon to see what the USB traffic is doing. The trafic stops all together when both USB devices are unplugged for the first time. The external USB HUB is still present in the device list but it does not detect anything after the last disconnect. [ 686.780928] usb 1-1.1: USB disconnect, device number 3 de249440 1778606192 C Ii:002:01 0 1 = 02 de249440 1778606263 S Ii:002:01 -115 1 < de37df40 1778606439 S Ci:002:00 s a3 00 0000 0001 0004 4 < de37df40 1778607418 C Ci:002:00 0 4 = 00010100 de37df40 1778607564 S Co:002:00 s 23 01 0010 0001 0000 0 de37df40 1778608186 C Co:002:00 0 0 de32dd40 1778617248 C Ii:003:01 -108 0 de79a2c0 1778663228 S Ci:002:00 s a3 00 0000 0001 0004 4 < de79a2c0 1778664392 C Ci:002:00 0 4 = 00010000 de310dc0 1778702124 S Ci:002:00 s a3 00 0000 0001 0004 4 < de310dc0 1778702417 C Ci:002:00 0 4 = 00010000 de310dc0 1778742058 S Ci:002:00 s a3 00 0000 0001 0004 4 < de310dc0 1778743170 C Ci:002:00 0 4 = 00010000 de310dc0 1778782078 S Ci:002:00 s a3 00 0000 0001 0004 4 < de310dc0 1778782276 C Ci:002:00 0 4 = 00010000 de310dc0 1778822059 S Ci:002:00 s a3 00 0000 0001 0004 4 < de310dc0 1778822254 C Ci:002:00 0 4 = 00010000 de249440 1778825402 C Ii:002:01 -2 0 de310dc0 1778828574 S Co:002:00 s 00 03 0001 0000 0000 0 de310dc0 1778830677 C Co:002:00 0 0 de310dc0 1778831792 S Co:001:00 s 23 03 0002 0001 0000 0 de310dc0 1778833243 C Co:001:00 0 0 de74b1c0 1778853787 C Ii:001:01 -2 0 ^C root@som3517:/sys/kernel/debug/usb/usbmon# lsusb Bus 001 Device 002: ID 0424:2512 Standard Microsystems Corp. USB 2.0 Hub Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub > > Alan Stern > -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
