[BRLTTY] Problem with brltty 3.9 on debian testing

[Nath]

On mar, fév 19, 2008 at 08:17:33 -0500, Dave Mielke wrote :
> [quoted lines by Nath on 2008/02/20 at 00:19 +0100]
> 
> >I have installed debian testing on my new Asus Eee pc and I encounter a
> >problem I never have had before : the braille display turns on sleep
> >mode every 4 or 5 seconds. when I press a key on the braille display or
> >on the laptop keyboard the braille display is up again but if I don't
> >press anything, 4 or 5 seconds after it is in sleep mode again.
> 
> You may be a victim of the automatic USB device suspension feature. Brltty 
> currently disables this feature for Baum displays, but not for others. Perhaps 
> it should arbitrarily disable it for all displays. Let's figure out if this is 
> your problem:
> 
> Go (cd) to /sys/class/usb_device. In that directory you'll find a bunch of 
> devices with names like usbdev1.2. The first digit is the bus number and the 
> second digit is the device number.
> 
> The next thing to do is to figure out which of those usbdevx.y devices 
> corresponds to your display. Each of them is a directory whcih contains, among 
> other things, a subdirectory named device. Each of those device subdirectories 
> contains, among other things, a file named manufacturer. So, for example, to 
> check usbdev1.2, see what usbdev1.2/device/manufacturer says. Find the one 
> which names the manufacturer of your display.
> 
> When you find the usbdevx.y device which corresponds to your display, cd to 
> usbdevx.y/device/power. In there you'll find a file called autosuspend. Write 
> -1 to it, like this (assuming usbdev1.2):
> 
>    cd usbdev1.2/device/power
>    echo >autosuspend -1
> 
> Please let us know if this resolves your problem. If so, brltty will be updated 
> to handle this problem automatically.
> 
> One important thing to note is that the usbdevx.y name will change each time 
> you disconnect and reconnect your display so don't do that after you've written 
> to its autosuspend file else you'll have to do it again.
> 
> -- 
> Dave Mielke           | 2213 Fox Crescent | I believe that the Bible is the
> Phone: 1-613-726-0014 | Ottawa, Ontario   | Word of God. Please contact me
> EMail: dave at mielke.cc | Canada  K2A 1H7   | if you're concerned about Hell.
> http://FamilyRadio.com/                   | http://Mielke.cc/bible/
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> 
Hi Dave & all,

I think you're right, the problem should be usb autosuspend but
unfortunatly writing -1 to
/sys/class/usb_device/usbdevx.y/device/power/autosuspend doesn't solve
it. Before I wrote -1 in the file the value was 2. There is 2 others
files in the power directory, level and wakeup. Wakeup contains the
value "enabled" and level contains the value "auto".
Instead of -1 I tried with 0 but the problem persists.
So perhaps I must modify another thing ? I'm going to search on the web
if others solutions exist to disable autosuspend mode. I hope not to
have to recompile the kernel.
If you have others suggestions to try to disable this, please let me
know !

Thx,





-- 
Nath