Re: Finding Aki M Laukkanen's VESAFBD project?

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 [off-list ref] wrote:

quoted

I noticed the email but I wasn't sure if you knew

about the code

quoted

from the way your mail was worded. 

;-)

quoted

I used fasync and poll to implement user space

communications in a

quoted

driver I just finished.  Use kill_fasync(&fasync,

SIGIO) from the

quoted

device driver to signal the user app. The signal

causes the app to

quoted

poll which the driver replies POLLIN to. Polling

identifies which

quoted

device caused the signal. Now the user app knows

it needs to IOCTL

quoted

the handle to do whatever the driver needs it to.

It only takes

quoted

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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