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Grant <emailgrant@×××××.com> [11-07-13 03:13]: |
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> >>> When I was using an Nvidia video card, I noticed a strange sort of |
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> >>> fuzzy edge effect if I used nvidia-drivers. xf86-video-nouveau didn't |
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> >>> have the same problem. Now I've switched to an ATI video card and |
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> >>> unfortunately I have the same problem with xf86-video-ati. I tried to |
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> >>> enable the new modesetting radeon driver in the kernel to see if that |
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> >>> would help but it doesn't work with my HD4250 card yet. Does anyone |
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> >>> know how to fix this? Here's a photo of the effect around the mouse |
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> >>> cursor: |
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> >>> |
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> >>> http://imageshack.us/photo/my-images/804/cursor.jpg |
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> >>> |
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> >>> - Grant |
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> >>> |
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> >> |
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> >> Hi Grant, |
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> >> |
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> >> just a shot in the dark: |
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> >> The image looks to me as thos would be an analog instead of |
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> >> an digital problem. |
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> >> May be both propietary drivers switch to the highest possible |
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> >> data transfer rate and this triggers the problem. |
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> >> To check, whether this may be the problem: |
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> >> Instruct the driver to use either low resolution or low refresh |
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> >> rates. Check both. |
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> >> If the problem changes signifiently: Change the cables. |
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> >> May be only a pluf is not inserted correctly. |
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> >> Addtionally you can move the cables arround to see whether |
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> >> this will change the shadows around the cursor in any way... |
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> >> |
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> >> Good luck! :) |
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> >> Best regards |
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> >> mcc |
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> > |
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> > Thanks for that. I'm still working on it but adding radeon.audio=0 to |
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> > grub cleaned it up about 75%. |
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> > |
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> > - Grant |
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> |
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> It turns out the radeon.audio=0 setting disables HDMI data packets and |
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> puts the HDMI port in DVI mode. mcc, I'm starting to think you had it |
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> pretty right on. I've tried two different cables with the same result |
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> but I'm thinking this may be some sort of electrical interference |
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> issue. I deal with stuff like that in audio. There's a USB isolator |
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> which cleans the sound way up when used with a USB sound card: |
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> |
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> http://www.analog.com/en/interface/digital-isolators/adum4160/products/product.html |
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> |
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> Now I wish there was something like that for HDMI. |
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> |
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> - Grant |
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> |
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|
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Hi Grant, |
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|
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another shot into an even much deeper dark .... ;) |
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|
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May be you have a problem here, which it is called "Brummschleife" |
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in german...sorry dont know the English equivalent...may be something |
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like "buzzing loop"...but this looks more like a strange translation |
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made by google than by any other, human being ;) |
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Anyway.... |
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|
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A "Brummschleife" happens when doing something like this: |
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|
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+----+ +-----------+ |
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--------------+ |-(1)----------------------+ monitor or|------------- |
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mains | PC |-(2)----------------------| amplifier | mains |
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--------------+ | (audio/USB/video or + or..... |------------- |
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-+------------+----+ another low voltage +-----------+-----------+- |
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| thingy) | |
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(3) (4) |
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| | |
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_ _ |
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ground ground |
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|
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|
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Normally all protective earth's connection should end in ONE point: A |
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copper rod or someting like this. |
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BUT often the wires between them are too long or there are two or |
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even more end points. Result: HF from near by broadcast stations, |
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60Hz mains frequency, ham radio station, microwave ovens and anything |
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which can emit energy, pushes protective earth to another electrical |
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potential than 0V. |
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Since both, PC and -- in your case -- the monitor are using |
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protective earth, they may be put on "another", may be even |
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varying (over time) electrical potentials. Since they are connected |
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via a two-wire connection WITHOUT protective earth (no, the shielding |
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is not for that purpose) the difference in the potential earth put |
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both ends to different electrical reference points. |
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This way you get an amplitude modulation of the signal between both |
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endpoint. In case of 60HZ you will hear a "Brummschleife" sound on |
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audio connection (a buzzing sound), in case of frequencies near |
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those of the video signal you will get "ghosts" in the monitor picture. |
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|
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Now, how to avoid that. |
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Hit the one who have made the protective earth connection in your |
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house. |
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While you are searching for that person, you can try the following: |
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Put all mains connectors of you PC rig into ONE wall connector |
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with something like this (ok I miss some words here again and |
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since a picture says more than even thousands of /missing/ words |
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here comes an image of what I mean:): |
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http://www.reichelt.de/Steckdosenleisten-ohne-Schalter/6-FACH-DOSE-WS-5/index.html?;ACTION=3;LA=2;ARTICLE=108651;GROUPID=4281;SID=11Thz@On8AAAIAABaBBrE9f5418078c2ea9fe6608e9765d978595 |
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|
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This way, all protective earth ends up in the same contact. No |
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differences in the electricla potential of the protective earth |
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anymore. |
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|
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Why does the those USB-isolatore-like cables help here? |
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|
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These small air core transformers (or in other words: There is |
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no core at all... ;) ) do a (german, sorry...) |
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"Gleichtaktunterdrueckung" which means, that any |
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potential difference (which is: the signal itsself) between |
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wire (1) and wire (2) is transmitted, and any modulating |
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difference of electrical potential between (3) and (4), |
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influencing (1) and (2) at the same time the same way will |
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be suppressed by the transformers. |
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|
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|
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Hopefully the theorectical aspect of this will not surpress |
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the practical success here ;) |
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|
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Good luck! |
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Best regards, |
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mcc |