OESF Portables Forum

Everything Else => Zaurus Distro Support and Discussion => Distros, Development, and Model Specific Forums => Archived Forums => Sharp ROMs => Topic started by: dhns on July 28, 2005, 06:15:49 am

Title: How To Get Vertical Retrace Interrupt?
Post by: dhns on July 28, 2005, 06:15:49 am
Is there a method to have a user space daemon synchronize with the vertical retrace on the standard Sharp kernel (2.4.x)?

The background is that I have a daemon that directly reads out the sharp_ts (touchscreen) device but shows a lot of jitter. Now, I guess that it is an interference with the LCD device and the Touchscreen resistive planes which drive the ADC.

So I want to test if I can synchronize reading of the ts device with the LCD.

Qt must have solved that since it does not show the jitter.

[Edited]
I have found two links for the OpenBSD zts.c driver (kernel) apparently addressing the same problem:
http://archives.neohapsis.com/archives/ope...05-04/0391.html (http://archives.neohapsis.com/archives/openbsd/cvs/2005-04/0391.html)
http://www.openbsd.org/cgi-bin/cvsweb/src/...x-cvsweb-markup (http://www.openbsd.org/cgi-bin/cvsweb/src/sys/arch/zaurus/dev/zts.c?rev=1.9&content-type=text/x-cvsweb-markup)

But this is in kernel and I don't want to write a new touch screen driver :-(

Any hints are welcome.

-- hns
Title: How To Get Vertical Retrace Interrupt?
Post by: ev1l on July 30, 2005, 06:39:39 am
At an OSS meeting in Austria I saw a couple of OpenBSD guys running OBSD on the SL-C3000. Your best bet might be to post on their kernel devel mailing list.
Title: How To Get Vertical Retrace Interrupt?
Post by: dhns on July 30, 2005, 02:58:29 pm
Quote
At an OSS meeting in Austria I saw a couple of OpenBSD guys running OBSD on the SL-C3000. Your best bet might be to post on their kernel devel mailing list.
[div align=\"right\"][a href=\"index.php?act=findpost&pid=90151\"][{POST_SNAPBACK}][/a][/div]
Many thanks for the answer.

I have already looked what they are doing. They have a special touchscreen driver - but that can't be ported back to Linux. And they might not know anything about the Linux 2.4.x system...

And what I unfortunately can't do is to install a different system just to get the touchscreen coordinates debounced  

-- hns