Hey,
Op 19-12-17 om 06:26 schreef Dhinakaran Pandiyan:
Convert the power_domains->domain_use_count array that tracks per-domain use count to atomic_t type. This is needed to be able to read/write the use counts outside of the power domain mutex.
Cc: Daniel Vetter daniel.vetter@ffwll.ch Cc: Ville Syrjälä ville.syrjala@linux.intel.com Cc: Rodrigo Vivi rodrigo.vivi@intel.com Signed-off-by: Dhinakaran Pandiyan dhinakaran.pandiyan@intel.com
drivers/gpu/drm/i915/i915_debugfs.c | 2 +- drivers/gpu/drm/i915/i915_drv.h | 2 +- drivers/gpu/drm/i915/intel_runtime_pm.c | 11 +++++------ 3 files changed, 7 insertions(+), 8 deletions(-)
diff --git a/drivers/gpu/drm/i915/i915_debugfs.c b/drivers/gpu/drm/i915/i915_debugfs.c index 1a7b28f62570..1f1d9162f2c2 100644 --- a/drivers/gpu/drm/i915/i915_debugfs.c +++ b/drivers/gpu/drm/i915/i915_debugfs.c @@ -2764,7 +2764,7 @@ static int i915_power_domain_info(struct seq_file *m, void *unused) for_each_power_domain(power_domain, power_well->domains) seq_printf(m, " %-23s %d\n", intel_display_power_domain_str(power_domain),
power_domains->domain_use_count[power_domain]);
atomic_read(&power_domains->domain_use_count[power_domain]));}
mutex_unlock(&power_domains->lock);
diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h index 1e4e613e7b41..ddadeb9eaf49 100644 --- a/drivers/gpu/drm/i915/i915_drv.h +++ b/drivers/gpu/drm/i915/i915_drv.h @@ -1489,7 +1489,7 @@ struct i915_power_domains { int power_well_count;
struct mutex lock;
- int domain_use_count[POWER_DOMAIN_NUM];
- atomic_t domain_use_count[POWER_DOMAIN_NUM]; struct i915_power_well *power_wells;
};
diff --git a/drivers/gpu/drm/i915/intel_runtime_pm.c b/drivers/gpu/drm/i915/intel_runtime_pm.c index 96ab74f3d101..992caec1fbc4 100644 --- a/drivers/gpu/drm/i915/intel_runtime_pm.c +++ b/drivers/gpu/drm/i915/intel_runtime_pm.c @@ -1453,7 +1453,7 @@ __intel_display_power_get_domain(struct drm_i915_private *dev_priv, for_each_power_domain_well(dev_priv, power_well, BIT_ULL(domain)) intel_power_well_get(dev_priv, power_well);
- power_domains->domain_use_count[domain]++;
- atomic_inc(&power_domains->domain_use_count[domain]);
}
/** @@ -1539,10 +1539,9 @@ void intel_display_power_put(struct drm_i915_private *dev_priv,
mutex_lock(&power_domains->lock);
- WARN(!power_domains->domain_use_count[domain],
"Use count on domain %s is already zero\n",
- WARN(atomic_dec_return(&power_domains->domain_use_count[domain]) < 0,
"Use count on domain %s was already zero\n", intel_display_power_domain_str(domain));
power_domains->domain_use_count[domain]--;
for_each_power_domain_well_rev(dev_priv, power_well, BIT_ULL(domain)) intel_power_well_put(dev_priv, power_well);
@@ -3049,7 +3048,7 @@ static void intel_power_domains_dump_info(struct drm_i915_private *dev_priv) for_each_power_domain(domain, power_well->domains) DRM_DEBUG_DRIVER(" %-23s %d\n", intel_display_power_domain_str(domain),
power_domains->domain_use_count[domain]);
atomic_read(&power_domains->domain_use_count[domain]));}
@@ -3092,7 +3091,7 @@ void intel_power_domains_verify_state(struct drm_i915_private *dev_priv)
domains_count = 0; for_each_power_domain(domain, power_well->domains)
domains_count += power_domains->domain_use_count[domain];
domains_count += atomic_read(&power_domains->domain_use_count[domain]);if (power_well->count != domains_count) { DRM_ERROR("power well %s refcount/domain refcount mismatch "
I can imagine this will start failing really badly. The previous code assumed that everything is protected by power_domains->lock, and now this changes makes it no longer the case..
I see the rest of the code changes things even more, but it would be better if the locking rework was done in a single patch, and not bolted on..
And instead of using atomic_t, there is a refcount implementation in refcount.h, it could be used here for locking power wells only if it would drop to zero..
Cheers, Maarten