Re: [gentoo-user] Problem with xf86-video-ati & nvidia-drivers

[Grant]

>>> When I was using an Nvidia video card, I noticed a strange sort of
>>> fuzzy edge effect if I used nvidia-drivers.  xf86-video-nouveau didn't
>>> have the same problem.  Now I've switched to an ATI video card and
>>> unfortunately I have the same problem with xf86-video-ati.  I tried to
>>> enable the new modesetting radeon driver in the kernel to see if that
>>> would help but it doesn't work with my HD4250 card yet.  Does anyone
>>> know how to fix this?  Here's a photo of the effect around the mouse
>>> cursor:
>>>
>>> http://imageshack.us/photo/my-images/804/cursor.jpg
>>>
>>> - Grant
>>>
>>
>> Hi Grant,
>>
>> just a shot in the dark:
>> The image looks to me as thos would be an analog instead of
>> an digital problem.
>> May be both propietary drivers switch to the highest possible
>> data transfer rate and this triggers the problem.
>> To check, whether this may be the problem:
>> Instruct the driver to use either low resolution or low refresh
>> rates. Check both.
>> If the problem changes signifiently: Change the cables.
>> May be only a pluf is not inserted correctly.
>> Addtionally you can move the cables arround to see whether
>> this will change the shadows around the cursor in any way...
>>
>> Good luck! :)
>> Best regards
>> mcc
>
> Thanks for that.  I'm still working on it but adding radeon.audio=0 to
> grub cleaned it up about 75%.
>
> - Grant

It turns out the radeon.audio=0 setting disables HDMI data packets and
puts the HDMI port in DVI mode.  mcc, I'm starting to think you had it
pretty right on.  I've tried two different cables with the same result
but I'm thinking this may be some sort of electrical interference
issue.  I deal with stuff like that in audio.  There's a USB isolator
which cleans the sound way up when used with a USB sound card:

http://www.analog.com/en/interface/digital-isolators/adum4160/products/product.html

Now I wish there was something like that for HDMI.

- Grant