[Intel-gfx] [PATCH v2] drm/i915/skl: Skip remaining dividers when deviation is 0
Daniel Vetter
daniel at ffwll.ch
Fri Jun 26 10:42:14 PDT 2015
On Fri, Jun 26, 2015 at 06:34:29PM +0100, Damien Lespiau wrote:
> We can't improve a 0 deviation, so when we find such a divider, skip the
> remaining ones they won't be better.
>
> This short-circuit the search for 34 of the 373 test frequencies in the
> corresponding i-g-t test (tools/skl_compute_wrpll)
>
> v2: Place the short-circuiting code in skl_compute_wrpll() (Paulo)
>
> (I'm sure nobody will notice the spurious removal of a blank line)
>
> Reviewed-by: Paulo Zanoni <paulo.r.zanoni at intel.com>
> Suggested-by: Paulo Zanoni <paulo.r.zanoni at intel.com>
> Signed-off-by: Damien Lespiau <damien.lespiau at intel.com>
Queued for -next, thanks for the patch.
-Daniel
> ---
> drivers/gpu/drm/i915/intel_ddi.c | 9 ++++++++-
> 1 file changed, 8 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpu/drm/i915/intel_ddi.c b/drivers/gpu/drm/i915/intel_ddi.c
> index f6b3ccc..42c1487 100644
> --- a/drivers/gpu/drm/i915/intel_ddi.c
> +++ b/drivers/gpu/drm/i915/intel_ddi.c
> @@ -1149,7 +1149,6 @@ static void skl_wrpll_try_divider(struct skl_wrpll_context *ctx,
> ctx->dco_freq = dco_freq;
> ctx->p = divider;
> }
> -
> }
>
> static void skl_wrpll_get_multipliers(unsigned int p,
> @@ -1315,9 +1314,17 @@ skl_ddi_calculate_wrpll(int clock /* in Hz */,
> dco_central_freq[dco],
> dco_freq,
> p);
> + /*
> + * Skip the remaining dividers if we're sure to
> + * have found the definitive divider, we can't
> + * improve a 0 deviation.
> + */
> + if (ctx.min_deviation == 0)
> + goto skip_remaining_dividers;
> }
> }
>
> +skip_remaining_dividers:
> /*
> * If a solution is found with an even divider, prefer
> * this one.
> --
> 2.1.0
>
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--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
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