Re: Finding Aki M Laukkanen's VESAFBD project?

[Jon Smirl <jonsmirl@yahoo.com>]

You can do it either way. With blocking IO you would
need one thread per adapter. With the signal method
you can be single threaded and sleep waiting for a
signal. Both styles will work.

With single threaded you make an array of handles for
the framebuffers. When you get a signal you do poll()
on the array. For each active poll you will need to do
the IOCTL. Keep looping on poll/IOCTL until the poll
goes inactive, then sleep waiting for a SIGIO.

--- Kendall Bennett <KendallB@scitechsoft.com> wrote:
> Jon Smirl <jonsmirl@yahoo.com> wrote:
> 
> > I noticed the email but I wasn't sure if you knew
> about the code
> > from the way your mail was worded. 
> 
> ;-)
> 
> > I used fasync and poll to implement user space
> communications in a
> > driver I just finished.  Use kill_fasync(&fasync,
> SIGIO) from the
> > device driver to signal the user app. The signal
> causes the app to
> > poll which the driver replies POLLIN to. Polling
> identifies which
> > device caused the signal. Now the user app knows
> it needs to IOCTL
> > the handle to do whatever the driver needs it to.
> It only takes
> > about 100 lines of code to implement the
> communication. 
> 
> Does the user space daemon block waiting to be woken
> up from the kernel 
> module? I think the way Aki had it done initially
> was to have the user 
> space daemon call into the kernel via an ioctl() or
> something, and the 
> kernel would block on that thread and when something
> needed to be done, 
> it would fill in the return structure for the
> ioctl() and then unblock 
> the thread. The user space daemon would process the
> ioctl() and and then 
> call it agin once the service was completed.
> 
> Does that system make sense at all?
> 
> Thanks!
> 
> ---
> Kendall Bennett
> Chief Executive Officer
> SciTech Software, Inc.
> Phone: (530) 894 8400
> http://www.scitechsoft.com
> 
> ~ SciTech SNAP - The future of device driver
> technology! ~
> 
> 
> 
>
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=====
Jon Smirl
jonsmirl@yahoo.com

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