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

[bugzilla-daemon@freedesktop.org]

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

           Summary: [patch] Radeon clocks should not be limited to
                    defaults
           Product: DRI
           Version: unspecified
          Platform: Other
        OS/Version: Linux (All)
            Status: NEW
          Severity: normal
          Priority: medium
         Component: DRM/Radeon
        AssignedTo: dri-devel@lists.freedesktop.org
        ReportedBy: ahlaht@gmail.com


Created an attachment (id=48691)
 --> (https://bugs.freedesktop.org/attachment.cgi?id=48691)
Do not limit clocks.patch

As of Linux 3.0-rc5 radeon_set_power_state() does not accept clock speeds
higher than the defaults set by firmware. However on my HP laptop the default
clock speeds are much lower than the maximum speeds accepted by the card.

These are the default values on my HP laptop:
engine 100000 kHz, memory 157000 kHz, vddc 900 mV

And the other values:

echo low > power_profile
power_state 4, clock_mode 0, engine 100000, memory 150000, vddc 900

echo mid > power_profile
power_state 4, clock_mode 1, engine 100000, memory 150000, vddc 900

echo high > power_profile
power_state 1, clock_mode 2, engine 100000, memory 157000, vddc 1000


The problem occurs with the "high" profile and also when using "dynpm". See the
provided patch, it fixes the problem. With the patch applied, correct
frequencies are set:

echo high > power_profile
power_state 1, clock_mode 2, engine 550000, memory 800000, vddc 1000

Now the question remains: why where those checks added in the first place? They
don't make sense to me unless default clock speeds are specified to be the
highest possible. Also there is no such check for voltage.

I do not know if this patch can break some other already broken systems, but
it's important to fix the problem somehow because it severely limits 3d
performance.

The hardware is AMD Mobility Radeon HD 5650 (1002:68C1).

I'm attaching a complete list of power states on this system. Also for
reference here are the values used by Windows 7 when on AC power (I forgot to
test battery power):

Win 7 Catalyst PowerPlay disabled:
engine 100000, memory 157000, vddc 900

Win 7 Catalyst PowerPlay enabled:
engine 100000, memory 150000, vddc 900   GPU idle
engine 450000, memory 800000, vddc 950   Light load
engine 550000, memory 800000, vddc 1000  Heavy load

The last 2 modes here are identical to what dynpm uses on Linux after the
patch.

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