[igt-dev] [RFC PATCH i-g-t v4 3/4] tests/gem_exec_reloc: Calculate offsets from minimum GTT alignment

[Chris Wilson]

Quoting Janusz Krzysztofik (2019-10-31 15:28:56)
> The basic-range subtest assumes 4kB GTT alignment while calculating
> softpin offsets.  On future backends with possibly larger minimum page
> sizes the test will fail as a half of calculated offsets to be tested
> will be incorrectly aligned.
> 
> Replace hardcoded constants corresponding to the assumed 4kB GTT
> alignment with variables initialized with actual minimum GTT alignment
> size and order.
> 
> v2: Simplify the code by reversing the size->order conversion,
>   - drop irrelevant modifications of requested object sizes.
> v3: Reword commit message after removal of patch "Don't filter out
>     addresses on full PPGTT" from the series,
>   - initialize page size order with an actual minimum returned by a new
>     helper (inspired by Chris).
> v4: Update the helper name, use the term 'minimum GTT alignment' across
>     the change, adjust variable names,
>   - refresh the commit message on top of the reintroduced patch that
>     fixes invalid offsets incorrectly assumed as occupied.
> 
> Signed-off-by: Janusz Krzysztofik <janusz.krzysztofik at linux.intel.com>
> Cc: Katarzyna Dec <katarzyna.dec at intel.com>
> Cc: Stuart Summers <stuart.summers at intel.com>
> Cc: Chris Wilson <chris at chris-wilson.co.uk>
Reviewed-by: Chris Wilson <chris at chris-wilson.co.uk>
-Chris