Radeon DPMS problems? backlight turns back on after a minute

Alex Deucher alexdeucher at gmail.com
Mon Apr 6 17:04:08 PDT 2009


On 4/6/09, Lowell Alleman <lowell at allemansonline.com> wrote:
> Are there any known issues with DPMS not working properly with the latest
> radeon driver?  I've found some old bugs that sound similar, but don't
> exactly match and the workarounds I've found seem to make a difference.
> Here is what I'm experiencing:
>
> My laptop (IBM T42, r300) LCD will not going into power saving mode on its
> own.  If I force it go into one of these modes, it only stays in that mode
> for a short period of time (a few seconds to a couple of minutes) before the
> screen turns back on again. I'm pretty sure this isn't due to any
> keyboard/mouse events (since the screen saver doesn't
>  pop up a login dialog) and I don't see any new events /var/log/acpid that
> correlate to the LCD being re-enabled.  However, every time the LCD turns
> back on, I do see the following message in the Xorg.0 log file:  "enable
> LVDS".  It appears that the X server still thinks that the DPMS mode is
> enabled, because "xset q" says that the monitor is still in "Suspend" (or
> whatever mode I forced it to be in) even after the LCD was turned on again.
>

It should work fine.  If you use xset sometimes events come in after
the command to the display comes back on.  try:
sleep5; xset dpms force off

>
> Here are some additional details about my setup, and what I've tried:
>
> Relevant output from "xset q":
> DPMS (Energy Star):
>  Standby: 600    Suspend: 660    Off: 1200
>  DPMS is Enabled
>   Monitor is On
>
> After the display has been disabled using "xset force suspend" the display
> shuts down.  If you check "xset q" it now reports "Monitor is in Suspend".
> A minute or so later the LCD is turned back on.  Now I can see screensaver
> (which is DPMS-aware, and therefore has been paused to save CPU cycles).  At
> this point, "xset q" still shows "Monitor is in Suspend".
>
> I've tried switching between EXA and XAA acceleration.  As of radeon v6.12.0
> XAA says it is not supported any more, but EXA doesn't appear to be the
> default yet.  (Not sure what that means; but in both cases this problems
> still occurs).  I've also tried adding the "NoPM" option, as I found as an
> old workaround suggested, but that didn't make a difference either.
>

XAA is still supported.  There is just no render accel with XAA on
r3xx and newer chips.  Blits/fills/lines/etc. are still accelerated
with XAA, but EXA is generally preferable.

>
> Versions:
>
> X.Org X Server 1.5.2
> Radeon driver:  6.12.0  (I compiled this locally for improved
> performance in latest release)
> Linux 2.6.27-11-generic #1 SMP Thu Jan 29 19:24:39 UTC 2009 i686 GNU/Linux
>  Kubuntu 8.10
> KDE 4.1.4
>
> I can provide additional info (xorg.conf and Xorg.0.log) if this is an
> unknown situation and those would be helpful to have.
>
> Thanks,
>
> - Lowell
>
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