Dear Maintainer,

I'm using the open source ati graphics with a 3-screen setup. After upgrading to unstable after the release of Jessie everything ran without issue.

I booted into a seperate install of Jessie on the same computer that had flgrx installed, and after rebooting into unstable one of the screens (connected by a HDMI cable) has acquired a distinct green tinge that obscures whatever the screen is trying to show. It is a sort of neon green.

This image is a graphical corruption bug - I took a screenshot using ksnapshot and on my other two screens the image dispaled withouth the green tinge.

The tinge is not present:
  * In the BIOS
  * When GRUB is active
  * Early in the boot process when the kernel is still printing text
  * On a separate Debian install on the same hardware, using fglrx

I tried changing the gamma settings of the screen and poking at the backlight settings but this did not help. Changing the gamma made a very slight difference but the tinge does nto seem to be caused by a rogue gamma setting.

At some points during, eg, shutdown my screens go blank - usually this is black but at present the green tinged screen goes straight green.

I can't test it because it will not go away, but I think this problem was caused by using the card with fglrx then restarting the computer.

It sounds like there might be a problem with the physical display
connection. Have you checked the connector seating at both ends, maybe
unplugging and re-plugging them, or even using a different cable?

I have not, but if I reboot the computer to an install of Jessie using
fglrx the tinge is not present; and it appeared shortly after updating to
Jessie + unstable. I'll try a few things with the cable & report back if
any of them have an impact, but the fglrx test suggests this problem is
100% fixable in software.

Owen Riddy
Email: owen.riddy@gmail.com
Mobile: 040 163 2663

I guess I misunderstood the comments about fglrx in your original
report. I agree it's probably a software bug then, though it's more
likely in the kernel driver than in the Xorg driver.

No worries.

It turns out that the problem was the "Color Format" of my screen. Dunno
what that is, but it was configuring poorly and the open source driver
seems happier when it is set to RGB rather than YCbCr. Maybe Catalyst is a
bit more forgiving or maybe there is some configuration issue here I don't
understand.

My problem is solved; there may still be a minor bug here in how the
auto-configuration of the driver works.

Owen Riddy
Email: owen.riddy@gmail.com
Mobile: 040 163 2663

Is it only the HDMI display that is problematic?  It might be HDMI
packet related.  Does your display support audio?  You can disable
HDMI packets by setting radeon.audio=0 on the kernel command line in
grub or at runtime using xrandr (e.g., xrandr --output HDMI-0 --set
audio off).  If that helps, can you try kernel 4.1?

Alex

The open source driver does not support YCbCr at the moment.

Alex

Thanks for that. So my problem has narrowed down a bit (it still happens
but I can fix it by changing the input colour format using the buttons on
the side of the screen). The screen switches to use YCbCr input format:

** When the computer is booted up
** When I log in using kdm
** When the screen switches off after a period of inactivity

I've used this screen for more than a year and it hasn't happened before.
Is there any reason that the driver might set the input colour format to
YCbCr, or is it possible for a Radeon card to set a hint for input colour
format that could persist across a reboot?


I'll try with the 4.1 kernel and see if anything changes.

Owen Riddy
Email: owen.riddy@gmail.com
Mobile: 040 163 2663

I booted up into the install with fglrx installed, looked through the
settings and found where the screen was being set to YCbCr, and set it to
RGB. On rebooting my green tinged screen was gone.

Thanks for your help.

Owen Riddy
Email: owen.riddy@gmail.com
Mobile: 040 163 2663