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<FONT face=Tahoma size=2><B>From:</B> xorg-bounces@lists.freedesktop.org
[mailto:xorg-bounces@lists.freedesktop.org] <B>On Behalf Of </B>Luca
Bezerra<BR><B>Sent:</B> Tuesday, June 02, 2009 11:20 AM<BR><B>To:</B> Luca
Bezerra; xorg@lists.freedesktop.org<BR><B>Subject:</B> Re: Switching between
virtual desktops<BR></FONT><BR></DIV>
<DIV></DIV><BR>
<DIV class=gmail_quote>
<DIV>So it'd only switch the output after it has switched a virtual desktop,
making sure one wouldn't switch without the other.<BR><SPAN
class=213004218-02062009><FONT face=Arial color=#800000
size=2> </FONT></SPAN></DIV></DIV></BLOCKQUOTE>
<DIV><SPAN class=213004218-02062009><FONT face=Arial color=#800000 size=2>If you
wait to switch monitors until after the virtual desktop has been switched, the
the new virtual desktop will be displayed on the old monitor! You have to do do
something more like this:</FONT></SPAN></DIV>
<DIV><SPAN class=213004218-02062009><FONT face=Arial color=#800000
size=2></FONT></SPAN> </DIV>
<DIV><SPAN class=213004218-02062009><FONT face=Arial color=#800000 size=2>while
(1) {</FONT></SPAN></DIV>
<DIV><SPAN class=213004218-02062009><FONT face=Arial color=#800000
size=2> tell video demux to ignore new
input</FONT></SPAN></DIV>
<DIV><SPAN class=213004218-02062009><FONT face=Arial color=#800000
size=2> switch virtual desktops</FONT></SPAN></DIV>
<DIV><SPAN class=213004218-02062009><FONT face=Arial color=#800000
size=2> tell video demux to output to new
monitor</FONT></SPAN></DIV>
<DIV><SPAN class=213004218-02062009><FONT face=Arial color=#800000
size=2> sleep</FONT></SPAN></DIV>
<DIV><SPAN class=213004218-02062009><FONT face=Arial color=#800000
size=2>}</FONT></SPAN></DIV>
<BLOCKQUOTE
style="PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #800000 2px solid; MARGIN-RIGHT: 0px">
<DIV class=gmail_quote><SPAN class=213004218-02062009><FONT face=Arial
color=#800000 size=2></FONT></SPAN> </DIV>
<DIV class=gmail_quote><SPAN class=213004218-02062009> </SPAN>A: Dont
worry, I know this isnt far from impossible, I also have doubts myself. The
thing is, my boss has assigned me to this project, and so far, I've given him
no concrete results, since every approach I've tried was a dead end. </DIV>
<DIV class=gmail_quote>As I've mentioned on an email to someone else (again,
Im terrible with names), Im pretty sure second hand hardware isnt really
affordable for this project, since we're inside a federal university, so every
expense in here has to be documented first, then approved by several
departments before the real money is released for the buying. I'm pretty sure
there'll be no approvals for 2nd hand pieces... 21323213213, Im also in favor
of using the existing multiterminal (with multiple graphics boards) solution.
Too bad its not up to me to decide :P<BR><SPAN class=213004218-02062009><FONT
face=Arial color=#800000 size=2> </FONT></SPAN></DIV></BLOCKQUOTE>
<DIV class=gmail_quote><SPAN class=213004218-02062009><FONT face=Arial
color=#800000 size=2>Uh, one of the most fundamental skills an engineer needs to
learn, and learn early, is how to tell his managers their latest "solution"
won't work. It's easier to get away with telling them that if you do have a
working solution. Therefore, let's make this whole problem rest on the HW guys
shoulders:</FONT></SPAN></DIV>
<DIV class=gmail_quote><SPAN class=213004218-02062009><FONT face=Arial
color=#800000 size=2></FONT></SPAN> </DIV>
<DIV class=gmail_quote><SPAN class=213004218-02062009><FONT face=Arial
color=#800000 size=2>Tell him that his hardware needs to capture the video
signal into one of six separate frame buffers. Your parallel port interface will
tell him which one or none. His hardware will then provide a continuous video
signal out to each of the six monitors connected to it. Users get nice stable
video, you get easy SW task, and boss gets to prove he's a wiz HW
designer.</FONT></SPAN></DIV>
<DIV class=gmail_quote><FONT face=Arial color=#800000 size=2></FONT> </DIV>
<DIV class=gmail_quote><SPAN class=213004218-02062009><FONT face=Arial
color=#800000 size=2>Now, having said all of that, I'd have questioned the whole
approach from the beginning:</FONT></SPAN></DIV>
<DIV class=gmail_quote><SPAN class=213004218-02062009><FONT face=Arial
color=#800000 size=2></FONT></SPAN> </DIV>
<DIV class=gmail_quote><SPAN class=213004218-02062009><FONT face=Arial
color=#800000 size=2>Where are the monitors coming from? If you're buying them,
then there is money to buy cheap, modern PCs to run each station. If the
monitors are surplus, then check with you university's surplus property
department about getting ahold of discarded computers.</FONT></SPAN></DIV>
<DIV class=gmail_quote><SPAN class=213004218-02062009><FONT face=Arial
color=#800000 size=2></FONT></SPAN> </DIV>
<DIV class=gmail_quote><SPAN class=213004218-02062009><FONT face=Arial
color=#800000 size=2>Why do users have to log in if all they are going to do is
use a single PDF reader? I assume the student don't have to log in before the
can read a book off the shelves. Instead of using virtual desktops, have your
app map/unmap the N copies of acroread/xpdf/... in sync with you parallel port
output. There's no reason to have a window manager or virtual desktops at
all.</FONT></SPAN></DIV>
<DIV class=gmail_quote><SPAN class=213004218-02062009><FONT face=Arial
color=#800000 size=2></FONT></SPAN> </DIV>
<DIV class=gmail_quote><SPAN class=213004218-02062009><FONT face=Arial
color=#800000 size=2>BTW, what are you doing about input? How are you planning
on handling N keyboards and N mice?</FONT></SPAN></DIV>
<DIV class=gmail_quote><SPAN class=213004218-02062009><FONT face=Arial
color=#800000 size=2></FONT></SPAN> </DIV>
<DIV class=gmail_quote><SPAN class=213004218-02062009><FONT face=Arial
color=#800000 size=2>Mike McDonald</FONT></SPAN></DIV>
<DIV class=gmail_quote><SPAN class=213004218-02062009></SPAN> </DIV>
<DIV class=gmail_quote><SPAN class=213004218-02062009><FONT face=Arial
color=#800000 size=2></FONT></SPAN> </DIV>
<DIV class=gmail_quote><SPAN class=213004218-02062009><FONT face=Arial
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