linux-dev - Linux kernel development work

Age	Commit message (Collapse)	Author	Files	Lines
2020-06-02	drm/i915: Fix global state use-after-frees with a refcount	Ville Syrjälä	1	-0/+3
	While the current locking/serialization of the global state suffices for protecting the obj->state access and the actual hardware reprogramming, we do have a problem with accessing the old/new states during nonblocking commits. The state computation and swap will be protected by the crtc locks, but the commit_tails can finish out of order, thus also causing the atomic states to be cleaned up out of order. This would mean the commit that started first but finished last has had its new state freed as the no-longer-needed old state by the other commit. To fix this let's just refcount the states. obj->state amounts to one reference, and the intel_atomic_state holds extra references to both its new and old global obj states. Fixes: 0ef1905ecf2e ("drm/i915: Introduce better global state handling") Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20200527200245.13184-1-ville.syrjala@linux.intel.com Reviewed-by: Stanislav Lisovskiy <stanislav.lisovskiy@intel.com> (cherry picked from commit f8c86ffa2800adc80adc679c84c45e0c6b027374) Signed-off-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
2020-01-31	drm/i915: Introduce better global state handling	Ville Syrjälä	1	-0/+87
	Our current global state handling is pretty ad-hoc. Let's try to make it better by imitating the standard drm core private object approach. The reason why we don't want to directly use the private objects is locking; Each private object has its own lock so if we introduce any global private objects we get serialized by that single lock across all pipes. The global state apporoach instead uses a read/write lock type of approach where each individual crtc lock counts as a read lock, and grabbing all the crtc locks allows one write access. Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20200120174728.21095-15-ville.syrjala@linux.intel.com Reviewed-by: Imre Deak <imre.deak@intel.com>