[Intel-gfx] [PATCH] drm/i915: Pick the first unused PLL once again

[Lucas De Marchi]

On Wed, Jan 30, 2019 at 08:13:59PM +0200, Ville Syrjälä wrote:
>From: Ville Syrjälä <ville.syrjala at linux.intel.com>
>
>commit 5b0bd14dcc6b ("drm/i915/icl: keep track of unused pll while
>looping") inadvertently (I presume) changed the code to pick the
>last unused dpll rather than the first unused one like we did before.
>
>While there should most likely be no harm in changing the order
>let's change back just to avoid a change in the behaviour. At
>least it might reduce the confusion when staring at logs (took
>me a while to figure out why DPLL1 being picked over DPLL0
>when the latter was most definitely available).


I assumed the no harm and simplest approach so I didn't bother
checking if the it was already set. So I'd not say it was
"inadvertently", it was on purpose.

But if it makes life easier to read the logs:

Acked-by: Lucas De Marchi <lucas.demarchi at intel.com>


Lucas De Marchi

>
>Cc: Lucas De Marchi <lucas.demarchi at intel.com>
>Cc: Paulo Zanoni <paulo.r.zanoni at intel.com>
>Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
>---
> drivers/gpu/drm/i915/intel_dpll_mgr.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
>diff --git a/drivers/gpu/drm/i915/intel_dpll_mgr.c b/drivers/gpu/drm/i915/intel_dpll_mgr.c
>index 8f70838ac7d8..0a42d11c4c33 100644
>--- a/drivers/gpu/drm/i915/intel_dpll_mgr.c
>+++ b/drivers/gpu/drm/i915/intel_dpll_mgr.c
>@@ -258,7 +258,8 @@ intel_find_shared_dpll(struct intel_crtc *crtc,
>
> 		/* Only want to check enabled timings first */
> 		if (shared_dpll[i].crtc_mask == 0) {
>-			unused_pll = pll;
>+			if (!unused_pll)
>+				unused_pll = pll;
> 			continue;
> 		}
>
>-- 
>2.19.2
>