[Intel-gfx] intel_gpu_top missing clocks

[Bragg, Robert]

On Thu, Jun 19, 2014 at 3:10 PM, Chris Healy <cphealy at gmail.com> wrote:

> 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?
>

That looks right, yep.


> 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?
>

I'm afraid it looks like that the i915_debugfs.c code may be the best
reference a.t.m; though maybe someone who's worked on that code (not me)
can give you a better answer.

That said though; it could make sense to update intel_gpu_top to query
debugfs for this information anyway; considering that it's more up to date
and that way the logic doesn't need to be duplicated. For example if you
take a look at overlay/gpu-freq.c in the intel_gpu_tools repo it looks like
there's already some precedent for doing just that. It also looks like the
utility code in overlay/debugfs.c can be used to make sure debugfs is
mounted.

Sorry I couldn't point you at good documentation for this; but hopefully
that's still of some help to you.

--
Regards,
Robert




> 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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