[Intel-gfx] intel_gpu_top missing clocks

Chris Healy cphealy at gmail.com
Thu Jun 19 16:10:26 CEST 2014


Hi Robert,

This information is helpful.  I am able to query the frequencies as you
mentioned.  My primary interest though is in getting support added to
intel_gpu_top.  It seems to me that intel_gpu_top has been coded to support
providing clock frequency data for a subset of Intel GPUs and that the
mobile Ivy Bridge GT2 chipset is not supported.  Would you agree with
this?  If so, I'd like to fix this but don't know where to look for the bit
descriptions for the necessary registers.  Can you point me to the
appropriate document?

Regards,

Chris


On Tue, Jun 17, 2014 at 7:43 PM, Bragg, Robert <robert.bragg at intel.com>
wrote:

> Hi Chris,
>
> You can query the nominal and maximum frequency of your GPU via debugfs,
> in case that is good enough for your needs. Depending on what kernel
> version you have you can try to cat
> /sys/kernel/debug/dri/0/i915_cur_delayinfo or with more recent versions,
> /sys/kernel/debug/dri/0/i915_frequency_info
>
> If you are curious about more details then it may be best to look at the
> drm driver code in
> drivers/gpu/drm/i915/i915_debugfs.c:i915_frequency_info().
>
> --
> Regards,
> Robert
>
> On Wed, Jun 18, 2014 at 1:55 AM, He, Shuang <shuang.he at intel.com> wrote:
>
>>  Hi, Chris
>>
>>          Let’s put you to the correct Mailing list for this topic first
>>
>>
>>
>> Thanks
>>
>>          --Shuang
>>
>> *From:* Chris Healy [mailto:cphealy at gmail.com]
>> *Sent:* Wednesday, June 18, 2014 1:15 AM
>> *To:* Eric Anholt; He, Shuang
>> *Subject:* intel_gpu_top missing clocks
>>
>>
>>
>> Eric, Shuang,
>>
>> I couldn't find an appropriate mailing list to report this on, so I'm
>> mailing the two of you as you've both touched the clock code in
>> intel_gpu_top.
>>
>> I'm running an Ivy Bridge Mobile chipset and trying to use intel_gpu_top
>> and intel_stepping to see the GPU clock frequencies.  In both cases, the
>> clocks are "unknown".
>>
>> When I look at the code, it seems that there's just no code path to
>> handle this devid, though I'm not sure as I'm not very good at
>> understanding code.  I see in intel_chipset.h that device id 0x0166 =
>> PCI_CHIP_IVYBRIDGE_M_GT2 and that none of the "if's" in print_clock_info
>> ultimately point to this device type.
>>
>> Do either of you know why this would be?  Is it just a case of coding for
>> the majority of chipset configurations?
>>
>> If it's just the case of it not yet being handled, I'd be open to trying
>> to add support for it if you could point me to the necessary chip
>> documentation.
>>
>> Regards,
>>
>> Chris
>>
>> _______________________________________________
>> Intel-gfx mailing list
>> Intel-gfx at lists.freedesktop.org
>> http://lists.freedesktop.org/mailman/listinfo/intel-gfx
>>
>>
>
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