[Intel-gfx] [PATCH v2 2/2] drm/i915: resize the GuC WOPCM for rc6

[Rodrigo Vivi]

Hi Peter,

This patch is required for the BXT firmware loading.  (Maybe/Probably
something similar for KBL is also required)
Do you have plans to fix this interpretation as Dave pointed and send
a new version?

Thanks,
Rodrigo.

On Wed, Feb 3, 2016 at 7:39 AM, Dave Gordon <david.s.gordon at intel.com> wrote:
> On 21/01/16 21:41, Jeff McGee wrote:
>>
>> On Thu, Jan 21, 2016 at 06:11:01PM +0000, Peter Antoine wrote:
>>>
>>> This patch resizes the GuC WOPCM to so that the GuC and the RC6 memory
>>> spaces do not overlap.
>>>
>>> Issue: https://jira01.devtools.intel.com/browse/VIZ-6638
>>> Signed-off-by: Peter Antoine <peter.antoine at intel.com>
>>> ---
>>>   drivers/gpu/drm/i915/i915_guc_reg.h     | 3 ++-
>>>   drivers/gpu/drm/i915/intel_guc_loader.c | 6 +++++-
>>>   2 files changed, 7 insertions(+), 2 deletions(-)
>>>
>>> diff --git a/drivers/gpu/drm/i915/i915_guc_reg.h
>>> b/drivers/gpu/drm/i915/i915_guc_reg.h
>>> index 685c799..cb938b0 100644
>>> --- a/drivers/gpu/drm/i915/i915_guc_reg.h
>>> +++ b/drivers/gpu/drm/i915/i915_guc_reg.h
>>> @@ -58,7 +58,8 @@
>>>   #define GUC_MAX_IDLE_COUNT            _MMIO(0xC3E4)
>>>
>>>   #define GUC_WOPCM_SIZE                        _MMIO(0xc050)
>>> -#define   GUC_WOPCM_SIZE_VALUE           (0x80 << 12)  /* 512KB */
>>> +#define   GUC_WOPCM_SIZE_VALUE         (0x80 << 12)    /* 512KB */
>>> +#define   BXT_GUC_WOPCM_SIZE_VALUE     (0x70 << 12)    /* 448KB */
>>>
>>>   /* GuC addresses below GUC_WOPCM_TOP don't map through the GTT */
>>>   #define       GUC_WOPCM_TOP                   (GUC_WOPCM_SIZE_VALUE)
>>
>> Should GUC_WOPCM_TOP be dynamically assigned the proper value, or is it
>> sufficient to leave at the max possible WOPCM size? If the later, might be
>> worth a comment.
>> -Jeff
>
>
> This isn't the right interpretation of these values.
>
> GUC_WOPCM_TOP is the value defining the top of the GTT address range NOT
> available to the GuC and hence where GuC-accessible objects must NOT be
> placed.
>
> GUC_WOPCM_SIZE_VALUE is the value written to the GUC_WOPCM_SIZE register,
> defining how much WOPCM space CAN be used.
>
> The former is an architectural constant (512K); the latter is a
> software-defined boundary between areas of memory within that range that are
> used for different purposes.
>
> Therefore, GUC_WOPCM_TOP must NOT be defined in terms of
> GUC_WOPCM_SIZE_VALUE, but GUC_WOPCM_SIZE_VALUE could be defined in terms of
> GUC_WOPCM_TOP, in particular as (GUC_WOPCM_TOP-reserved).
>
> .Dave.
>
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-- 
Rodrigo Vivi
Blog: http://blog.vivi.eng.br