[elrepo] package suggestion: USB DisplayLink drivers and X11 driver

[Phil Perry]

On 10/06/11 06:02, Covert wrote:
>    On 6/9/11 4:08 PM, Phil Perry wrote:
>>
>> Hi Greg,
>>
>> This certainly sounds interesting and like a candidate for elrepo.
>> You've done a great job of "selling" it to me :-)
>>
>> I have a couple questions that I'm hoping you might be able to help with.
>>
>> Are you thinking el5, el6 or both?
>>
>> I've had a very quick look around the above wiki site. There are a
>> couple "kernel" driver branches available - the udlfb.ko driver in the
>> mainline kernel which we could backport and the displaylink-mod listed
>> on the above wiki. Which did you have in mind, and why? I'm guessing we
>> would prefer to backport the official kernel driver as that's the only
>> one ever likely to end up officially supported in RHEL.
>>
>> Can you point me to the X11 drivers we should be looking at please.
>>
>> Have you actually managed to build any of this on el6 and get it
>> working? If so, that would be an immense help.
>>
>> If we build packages, can you help with testing them? We don't have the
>> necessary hardware which always makes it difficult.
>>
>> Regards,
>>
>> Phil
> Hi Phil,
>
> Glad it piqued your interest!  I currently run SL6, so I would be most
> interested in EL6 drivers, but for the use case above, I think it would
> be easily useful for EL5.
>

Great. Lets start with el6 and we can migrate the packages to el5 later 
if possible.

> This page gives a very step by step set of instructions for enabling the
> "plug a whole console into a server" scenario for EL6:
> http://otb.bg/blog/usb-multiseat-on-red-hat-enterprise-linux-6/252
>
> They call it "multiseat", but really a keyboard, mouse, and usb video
> card all attached to a single USB hub plugged into a server, where an
> GDM and Xorg are started up dynamically when you attach the hub.  The
> most complicated part of these instructions is actually that the version
> of GDM in EL6 is too new -- the technique they describe uses a feature
> that was removed from recent versions, but actually in EL5 (which is why
> I said that EL5 would be handy.)
>

OK, I did quickly scan that page yesterday. I'm not particularly keen to 
mess with GDM, at least in an elrepo sense. Is this still useful if 
elrepo just provides the kernel and X11 drivers?

> Now, here's where I make a little confession.  :)  I used that use case
> as I thought it would be most interesting to this audience, but I
> actually want to use these drivers to extend my desktop over to an extra
> monitor I have on my desk.  I have one of these really neat little
> monitors:  http://www.thinkgeek.com/computing/usb-gadgets/bfa3/
>
> I have several machines plugged into a USB-DVI KVM.  I can switch
> between macs, windows, and linux machines, and when I switch to them
> (other than EL6) my desktop automatically extends over to the USB
> monitor.  The KVM has a mode where you can switch keyboard and display,
> but leave all of the USB devices attached to the previous machine.  So I
> move interesting things to the small monitor, then switch only
> keyboard+display to another machine, and I can keep an eye on both machines.
>
> So I do have the hardware (and can help test) -- I have not got it
> working through directly installing everything on my EL machine, but it
> did work back when I was using Ubuntu 10.04.
>

To kick off the development effort, it would be useful if you could get 
it up and running on your system built from source so you know exactly 
what's required for it to work. You would then be able to advise us 
better on packaging the components. But if it's a big deal, don't worry 
- I think we probably have enough to attempt a first build and we can 
take it from there.

> The Xorg drivers can be found here:
> http://libdlo.freedesktop.org/wiki/xf86-driver-displaylink
>

Thanks.

> I think the official udlfb driver in the kernel would fine for me.  When
> I was setting this up on Ubuntu, I found these in the repo, so was able
> to start doing the Xorg config right after installing the kernel module
> and the Xorg driver.  Here's an example of what the process sort of
> looks like on Ubuntu (though now the drivers are in the repo, so I
> didn't have to compile myself.)
> http://mulchman.org/blog/?tag=displaylink
>

OK, I propose we start by attempting to backport the official kernel 
udlfb driver from the upstream kernel as a kmod package and also package 
the accompanying X11 drivers, for el6.

My next problem is a shortage of time atm due to work commitments. Does 
anyone want to pick this up and run with it, or I can hopefully make a 
start sometime over the next couple weeks. If I pick it up, 
realistically it's not going to get done in the next week :-)

Regards,

Phil