On Wed, Feb 01, 2012 at 11:55:44AM +0000, Chris Wilson wrote:
On Wed, 1 Feb 2012 11:38:35 +0100, Sascha Hauer s.hauer@pengutronix.de wrote:
The drivers currently check in set_property whether the property is unchanged. move this check into the core and do not bother the drivers with checking for unchanged properties.
This patch seems to have functional side-effects beyond the description.
For example,
diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c index db3b461..0024b59 100644 --- a/drivers/gpu/drm/i915/intel_dp.c +++ b/drivers/gpu/drm/i915/intel_dp.c @@ -2223,9 +2223,6 @@ intel_dp_set_property(struct drm_connector *connector, int i = val; bool has_audio;
if (i == intel_dp->force_audio)return 0;Here we are checking against the current value of the intel_dp, which may in theory be modified elsewhere as well, and avoiding the modeswitch if it is unnecessary.
In case of force_audio I just checked that the current value is not changed elsewhere, but I must admit that I haven't checked this for all other properties. Would the patch be ok if I review for side effects?
BTW if someone changes the underlying variable of a property outside of the .set_property callback there are likely problems elsewhere because without calling drm_connector_property_set_value the values of the variable and the property backing store will be inconsistent. The calls to drm_connector_property_set_value in turn are quite easy reviewable, those are very few.
Sascha