Sony G520 CRT snaps on mode switch

[Alex Deucher]

On Fri, Dec 5, 2014 at 3:55 AM, Felix Miata <mrmazda at earthlink.net> wrote:
> I have an rv516 card:
> http://fm.no-ip.com/Tmp/Linux/hwinfo-gfx-rv516-big41.txt
>
> In as many different machines and with as many different Linux distros and
> versions I've tried this with (always FOSS X drivers, and IIRC, all with KMS
> kernels), I don't think there are any that don't ever exhibit $SUBJECT. I do
> a lot of switching between KDE3 & 4 and the vttys, so this is annoying, and
> makes me wonder if it could be damaging the CRT for this to happen.
>
> The "snapping" manifests different to different extents. Sometimes the screen
> just goes black then redraws. Other times in addition, the going black is
> accompanied by an audible snap noise. A mode switch (aka to or from KDE and a
> vtty) isn't required, but can be induced by running the attached script that
> includes xrdb and xrandr commands.
>
> Last booted was openSUSE 13.1, server 1.14.3.901, radeon driver
> xf86-video-ati-7.2.0-2.4.1, libdrm_radeon1-2.4.46-3.2.2 from which I got no
> snapping sound.
>
> Does this sound like a software issue, or hardware? If software, kernel, or X
> driver?

It's pretty common with CRTs and is a normal part of the mode switch process:

http://www.tomshardware.com/forum/2734-3-clicking-sound

Alex