fp dithering not same as nVidia's proprietary driver dithering

[klerfayt]

right, so using nv driver and Option "FPDither" won't result in same image quality as proprietary driver solution
I can see very tiny grid/pattern in window background, it reminds me of jeans (if that makes any sense to you)
not using fpdither is about same as nvidia's Option "FlatPanelProperties" "Dithering = Disabled"
+ also Option "FPDither" results in slower desktop, that is not appearing with nvidia's drivers

[Bryce Harrington (bryce)]

Thanks for reporting this bug. Could you take screenshots of each of the two cases and attach them? This will give a clue if the issue is in the rendering or elsewhere.

[klerfayt (klerfayt-deactivatedaccount)]

I did something more clever - I let webcam record my lcd screen from very close, opened kopete, went to camera settings and took screenshot of the desktop
what's more - if you change background (wallpaper) to be of one color #6E6E6E - the pattern I'm talking about with "FPDither" (then using nv driver of course) option will become very visible.

as you can see on the screenshot background is totally normal itself (at least for me if I switch to "nvidia" proprietary" driver)

notebook has this tft lcd screen:
http://www.samsung.com/Products/TFTLCD/NotePC/LTN154X1/LTN154X1.htm
(warning view with adobe flashplayer disabled this page)

[Bryce Harrington (bryce)]

klerfayt reports (https://bugs.launchpad.net/ubuntu/+source/xorg/+bug/115440) that when using Option "FPDither" with nv, it produces different results with lower image quality than when using the proprietary nvidia driver.

"right, so using nv driver and Option "FPDither" won't result in same image quality as proprietary driver solution I can see very tiny grid/pattern in window background, it reminds me of jeans (if that makes any sense to you)
not using fpdither is about same as nvidia's Option "FlatPanelProperties" "Dithering = Disabled" + also Option "FPDither" results in slower desktop, that is not appearing with nvidia's drivers"

[Bryce Harrington (bryce)]

Created an attachment (id=10115)
xorg.conf

[Bryce Harrington (bryce)]

Created an attachment (id=10116)
Xorg.0.log

[Bryce Harrington (bryce)]

Created an attachment (id=10117)
Screenshot

"I let webcam record my lcd screen from very close, opened kopete, went to camera settings and took screenshot of the desktop
what's more - if you change background (wallpaper) to be of one color #6E6E6E - the pattern I'm talking about with "FPDither" (then using nv driver of course) option will become very visible.

as you can see on the screenshot background is totally normal itself (at least for me if I switch to "nvidia" proprietary" driver)

notebook has this tft lcd screen:
http://www.samsung.com/Products/TFTLCD/NotePC/LTN154X1/LTN154X1.htm
(warning view with adobe flashplayer disabled this page)"

[Bryce Harrington (bryce)]

Thanks for the screenshot and additional information; I've filed this one upstream at https://bugs.freedesktop.org/show_bug.cgi?id=11085.

[Chris Halse Rogers (raof)]

The nouveau driver also exhibited the same sort of dithering artifacts for me, and this was recently fixed in git commit 91ca67056cb236e5770d4fb39dd7fbb9818ff093. Perhaps this fix can be ported from the nouveau drivers?

[Chris Halse Rogers (raof)]

For what it's worth, the nouveau driver handles this correctly (and I've commented as such on the upstream bug). It might be a fun exercise for someone to port the nouveau git commit to the nv tree :).

[Bryce Harrington (bryce)]

Thank you for reporting this issue about xserver-xorg-video-nv. Starting
with Lucid, Ubuntu is transitioning to using the -nouveau video driver
by default instead of -nv. The reason for this change is because
upstream development for the -nv driver has been quite slow. We are
quite pleased with the upstream development speed for -nouveau, and hope
this will translate into swifter bug fixes as well.

Because of this, I'm closing this bug report at this time. I'm marking
it wontfix because what you describe is probably a valid issue, but we
do not have further plans to work on it in Ubuntu. If you would still like
to see this issue investigated, I would encourage you to file it
upstream at http://bugs.freedesktop.org/.