[Intel-gfx] [PATCH 1/2] drm/i915: Compute the fw_domain id from the mask

[Chris Wilson]

On Mon, May 15, 2017 at 11:18:11AM +0100, Tvrtko Ursulin wrote:
> 
> On 12/05/2017 14:53, Chris Wilson wrote:
> >Storing both the mask and the id is redundant as we can trivially
> >compute one from the other. As the mask is more frequently used, remove
> >the id.
> >
> >Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> >Cc: Mika Kuoppala <mika.kuoppala at intel.com>
> >Cc: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
> >---
> > drivers/gpu/drm/i915/i915_debugfs.c |  2 +-
> > drivers/gpu/drm/i915/intel_uncore.c | 12 ++++++------
> > drivers/gpu/drm/i915/intel_uncore.h |  6 ++----
> > 3 files changed, 9 insertions(+), 11 deletions(-)
> >
> >diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c
> >index bd9abef40c66..a2c9c3e792e1 100644
> >--- a/drivers/gpu/drm/i915/i915_debugfs.c
> >+++ b/drivers/gpu/drm/i915/i915_debugfs.c
> >@@ -1468,7 +1468,7 @@ static int i915_forcewake_domains(struct seq_file *m, void *data)
> >
> > 	for_each_fw_domain(fw_domain, i915, tmp)
> > 		seq_printf(m, "%s.wake_count = %u\n",
> >-			   intel_uncore_forcewake_domain_to_str(fw_domain->id),
> >+			   intel_uncore_forcewake_domain_to_str(fw_domain),
> > 			   READ_ONCE(fw_domain->wake_count));
> >
> > 	return 0;
> >diff --git a/drivers/gpu/drm/i915/intel_uncore.c b/drivers/gpu/drm/i915/intel_uncore.c
> >index 08d7d08438c0..7eaa592aed26 100644
> >--- a/drivers/gpu/drm/i915/intel_uncore.c
> >+++ b/drivers/gpu/drm/i915/intel_uncore.c
> >@@ -40,8 +40,10 @@ static const char * const forcewake_domain_names[] = {
> > };
> >
> > const char *
> >-intel_uncore_forcewake_domain_to_str(const enum forcewake_domain_id id)
> >+intel_uncore_forcewake_domain_to_str(const struct intel_uncore_forcewake_domain *d)
> > {
> >+	unsigned int id = ilog2(d->mask);
> >+
> > 	BUILD_BUG_ON(ARRAY_SIZE(forcewake_domain_names) != FW_DOMAIN_ID_COUNT);
> >
> > 	if (id >= 0 && id < FW_DOMAIN_ID_COUNT)
> >@@ -77,7 +79,7 @@ fw_domain_wait_ack_clear(const struct drm_i915_private *i915,
> > 			     FORCEWAKE_KERNEL) == 0,
> > 			    FORCEWAKE_ACK_TIMEOUT_MS))
> > 		DRM_ERROR("%s: timed out waiting for forcewake ack to clear.\n",
> >-			  intel_uncore_forcewake_domain_to_str(d->id));
> >+			  intel_uncore_forcewake_domain_to_str(d));
> > }
> >
> > static inline void
> >@@ -95,7 +97,7 @@ fw_domain_wait_ack(const struct drm_i915_private *i915,
> > 			     FORCEWAKE_KERNEL),
> > 			    FORCEWAKE_ACK_TIMEOUT_MS))
> > 		DRM_ERROR("%s: timed out waiting for forcewake ack request.\n",
> >-			  intel_uncore_forcewake_domain_to_str(d->id));
> >+			  intel_uncore_forcewake_domain_to_str(d));
> > }
> >
> > static inline void
> >@@ -209,7 +211,7 @@ intel_uncore_fw_release_timer(struct hrtimer *timer)
> > 	struct intel_uncore_forcewake_domain *domain =
> > 	       container_of(timer, struct intel_uncore_forcewake_domain, timer);
> > 	struct drm_i915_private *dev_priv =
> >-		container_of(domain, struct drm_i915_private, uncore.fw_domain[domain->id]);
> >+		container_of(domain, struct drm_i915_private, uncore.fw_domain[ilog2(domain->mask)]);
> 
> Not sure I see the benefit of removing one field and then needing
> this ilog2 in the timer callback.

Timer was infrequent enough compared to the other paths that the extra
instruction seemed a matter of little concern, and out of the way.
-Chris

-- 
Chris Wilson, Intel Open Source Technology Centre