[Intel-gfx] [PATCH v3] drm/i915: resize the GuC WOPCM for rc6

[Dave Gordon]

On 05/05/2016 15:02, Antoine, Peter wrote:
> The attached version still does not explain that the WOPCM_TOP is to tell the GuC not to use that space.

That's NOT what WOPCM_TOP means. The GuC is allowed to use the space up 
to the value stored in the GUC_WOPCM_SIZE register (as the comment above 
the #define says). Architecturally, this is allowed to be any value 
greater than (16K+sizeof internal SRAM (64, 128, or 256K)) and less than 
or equal to GUC_WOPCM_TOP (which is a platform-independent constant), so 
we normally choose the maximm allowed. Howver on BXT, we need to leave 
some space at the top for the RC6 image, hence the logic (and comments!) 
in guc_wopcm_size().

> The extra information does not aid anybody as the information is used internally within the GuC.
It may help the next person who has to figure out what's gone wrong on 
some future chip that needs more than 64K for RC6!

.Dave.
>
> But, I have not actual objection to the patch.
>
> Peter.
>

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