[Bug 38917] [patch] Radeon clocks should not be limited to defaults

bugzilla-daemon at freedesktop.org bugzilla-daemon at freedesktop.org
Mon Jul 18 01:55:57 PDT 2011


https://bugs.freedesktop.org/show_bug.cgi?id=38917

Antti Lahtinen <ahlaht at gmail.com> changed:

           What    |Removed                     |Added
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  Attachment #48691|0                           |1
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--- Comment #3 from Antti Lahtinen <ahlaht at gmail.com> 2011-07-18 01:55:57 PDT ---
Created an attachment (id=49237)
 View: https://bugs.freedesktop.org/attachment.cgi?id=49237
 Review: https://bugs.freedesktop.org/review?bug=38917&attachment=49237

Add power_table in /sys

Here is an another patch I was asked to send. It unfortunately does not add
temperature monitoring, but it allows the user to remove the limit optionally.

It adds two new files in /sys/class/drm/card0/device: power_table and
allow_overclocking.

power_table contains the system specific list of power states and some extra
information. The whole file or just parts of it can be written back to change
some of the values run-time.

These 5 values can be changed on each clock mode:
- RADEON_PM_MODE_NO_DISPLAY (It may be useful to remove this flag to enable
  the lowest clock mode for dynpm.)
- engine clock
- memory clock
- vddc
- vddci

The changes actually done are printed to dmesg. Currently the power state is
not automatically reset after a change has been made. This must be done
manually by switching to another clock mode temporarily:
echo high > /sys/class/drm/card0/device/power_profile
echo mid > /sys/class/drm/card0/device/power_profile

For safety the clock rates and voltages can not be set to unlimited values by
default. The safety checks can be disabled with:
echo 1 > /sys/class/drm/card0/device/allow_overclocking

(This should also be done on systems affected by this bug.)

Of course incorrect combinations of clock rates and voltage can still crash the
system even with the checks enabled, but hopefully without permanent damage.

This new patch should not change the default behavior in any way other than
printing an error if the boot up clocks appear to be low.

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