[BRLTTY] powerpc linux machine running brltty on usb switch

[Cheryl Homiak]

Here is a brief description of my setup. I have a 4 by 4 usb switch which has  built-in cables that attach to up to four computers and slots for inserting the usb cables of four different devices. When the switch button is pressed, all four devices will then be operable on the selected computer. Currently I have a usb keyboard, a flatbed scanner, and my Hims Braille Edge attached to the switch. The switch is hooked up to a MacBook Air running Yosemite, an iMac running Mavericks and a Mac Mini running Lion (that one isn’t able to upgrade any further). Also attached is an old powerpc running debian wheezy linux. All machines also have brltty installed. With an occasional glitch here and there, the switch works fine with the three machines running Mac OS and I can access either brltty or voiceover braille and I can also run voiceover so I can use its speech in all windows but still run brltty in terminal as long as I turn off voiceover, start brltty in screen or let it come back up if already started, and then restart voiceover. In switching, though, there are times when voiceover does grab back control from brltty but this is not usually hard to reverse. It is a little complicated with both brltty and voiceover involved and it’s not perfect, but it works well enough to make it worth using the switch. Brltty must run in screen on the Macs but is running as a normal linux install on the powerpc linux machine.

My problem arises with brltty on  the powerpc machine running linux. When started it works. However when the switch is used to switch from that machine and then back again, the scanner and keyboard work but the braille display does not respond to the change to that machine though it responds to changes to all other machines. Once I have switched to the powerpc machine, the braille display still shows what was on the last machine but is no longer active with that machine either. However, as soon as I press a key (a keystroke not enter) on the keyboard also attached to the switch or if I type a character using a braillelite attached separately to the computer, then the Hims Braille Edge immediately becomes fully operable on the linux machine. This does of course in the end work but I’d like to have this work without having to press a key on some other device each time I switch back to the powerpc machine. I have attached a log, which just ran with debug, to see if anybody can explain this to me and tell me if there is a solution other than that of pressing a key on another device to bring the Hims Braille Edge back into action. The usb keyboard which also switches between the four machines at present, does not have any problem with switching to the linux machine each time the switch is used to select it. Thanks much for any help, advice or explanation re: this problem. I started brltty running the log, did a couple of characters, switched and then came back, typed a key on another keyboard which activated the Braille Edge on that computer again, and typed at least one character once re-engaged.


Cheryl Homiak


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