[ltp] Older radeon under ubuntu 10.04

Laurent linux-thinkpad@linux-thinkpad.org
Mon, 24 May 2010 15:29:53 +0200


i installed ubuntu 10.04 on a R51 (M7 / Radeon 7500) and have problems
with the suspend-to-ram. ClockGating and DynamicPM are enabled in xorg,
KMS is disabled via kernel parameter radeon.modeset=0. Kernel
2.6.32-22, Xorg 2:1.7.6-2ubuntu7.

In Suspend-to-RAM the backlight is off, but the display is on => 9cell
battery goes flat in one day.

Loading the module radeonfb to get D2 sleep outputs the usual dmesg
(radeonfb: IBM Thinkpad R51/T40/T41/T42 detected, enabling workaround).
Display and backlight are now off in suspend.

But the 2 systems are both trying to enable powersave on the chip:
"radeonfb: Dynamic Clock Power Management enabled" and
rovclock -i reports very high core (520MHz) and mem (365MHz)

And the system emits a high pitched noise during suspend. Not very
loud, but enough to make me wonder:

What is the best way to save power in Xorg and have a useful

Will the combination with radeonfb fry the chip? I did not dare to
test the suspend-to-RAM power consumption. The noise does not sound

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