A deadlock was caused by holding `trapMutex` while waiting on the lock of a resource inside a callback while another thread holding the resource's mutex waits on `trapMutex`. This has been fixed by no longer allowing blocking locks inside the callbacks and introducing a separate callback for locking the resource which is done after unlocking the `trapMutex` which can then be locked by any contending threads.
The `end` pointer for `interval` was incorrectly calculated as `interval.data() + interval.size_bytes()` which would be incorrect when the interval span type is not `u8` as the pointer derived from `interval.data()` would be a pointer to the span type rather than a byte pointer and be subject to arithmetic of that object's size rather than in terms of a byte.
We generally don't need to lock the `Texture`/`Buffer` in the trap handler, this is particularly problematic now as we hold the lock for the duration of a submission of any workloads. This leads to a large amount of contention for the lock and stalling in the signal handler when the resource may be `Clean` and can simply be switched over to `CpuDirty` without locking and utilizing atomics which is what this commit addresses.
We utilized a `FenceCycle` to keep track of if the buffer was mutable or not and introduced another cycle to track GPU-side requirements only on fulfillment of which could the buffer be utilized on the host but due to the recent change in the behavior this system ended up being unoptimal.
This commit replaces the cycle with a boolean tracking if there are any usages of the resource on the GPU within the current context that may prevent it from being mutated on the CPU. The fence of the context is simply attached to the buffer based off this which was allowed as the new behavior of buffer fences matches all the requirements for this.
An atomic transactional loop was performed on the backing `std::shared_ptr` inside `BufferView`/`TextureView`'s `lock`/`LockWithTag`/`try_lock` functions, these locks utilized `std::atomic_load` for atomically loading the value from the `shared_ptr` recursively till it was the same value pre/post-locking.
This commit abstracts the locking functionality of `TextureView`/`BufferDelegate` into `LockableSharedPtr` to avoid code duplication and removes the usage of `std::atomic_load` in either case as it is not necessary due to the implicit memory barrier provided by locking a mutex.
`PresentationEngine` and `GraphicBufferProducer` methods that utilized textures for the surface utilized the `Texture` type rather than the `TextureView` type, this was never correct but at the time of authoring this code `TextureView` was not finalized and in a major flux which is why it was not utilized and `Texture` was utilized instead. Now that is is far more stable, it has been replaced with `TextureView`.
We want to block on the host thread during presentation while the host surface isn't present to implicitly pause the game, this can end up being fairly costly as it involves locking the `PresentationEngine` mutex which can lead to a lot of contention with the presentation thread. This fixes the issue by polling if there is a surface and only if there isn't then doing the wait as it isn't mandatory to wait always, we'll eventually run into the guest thread stalling.
Newer versions of the Deko3D homebrew were crashing due to this check and it was discovered that the check was incorrect and rather than comparing the `NvSurface` what had to be compared was the `GraphicBuffer` associated with the slot directly.
Co-authored-by: lynxnb <niccolo.betto@gmail.com>
The copyright headers for external project such as yuzu/Ryujinx were inconsistent in ordering, Skyline should always be the first item in the list. In addition, they didn't always link to the project's GitHub which has also been fixed.
Multiple threads concurrently accessing the `TextureManager`/`BufferManager` (Referred to as "resource managers") has a potential deadlock with a resource being locked while acquiring the resource manager lock while the thread owning it tries to acquire a lock on the resource resulting in a deadlock.
This has been fixed with locking of resource manager now being externally handled which ensures it can be locked prior to locking any resources, `CommandExecutor` provides accessors for retrieving the resource manager which automatically handles locking aside doing so on attachment of resources.
GPU resources have been designed with locking by fences in mind, fences were treated as implicit locks on a GPU, design paradigms such as `GraphicsContext` simply unlocking the texture mutex after attaching it which would set the fence cycle were considered fine prior but are unoptimal as it enforces that a `FenceCycle` effectively ensures exclusivity. This conflates the function of a mutex which is mutual exclusion and that of the fence which is to track GPU-side completion and led to tying if it was acceptable to use a GPU resource to GPU completion rather than simply if it was not currently being used by the CPU which is the function of the mutex.
This rework fixes this with the groundwork that has been laid with previous commits, as `Context` semantics are utilized to move back to using mutexes for locking of resources and tracking the usage on the GPU in a cleaner way rather than arbitrary fence comparisons. This also leads to cleaning up a lot of methods that involved usage of fences that no longer require it and therefore can be entirely removed, further cleaning up the codebase. It also opens the door for future improvements such as the removal of `hostImmutableCycle` and replacing them with better solutions, the implementation of which is broken at the moment regardless.
While moving to `Context`-based locking the question of multiple GPU workloads being in-flight while using overlapping resources came up which brought a fundamental limitation of `FenceCycle` to light which was that only one resource could be concurrently attached to a cycle and it could not adequately represent multi-cycle dependencies. `FenceCycle` chaining was designed to fix this inadequacy and allows for several different GPU workloads to be in-flight concurrently while utilizing the same resources as long as they can ensure GPU-GPU synchronization.
If we want to allow submitting multiple pieces of work to the GPU at once while still requiring CPU synchronization, we'll need to track all past fence cycles associated with a resource alongside the current one. To solve this the concept of chaining fences has been introduced, fences from past usages can be chained to the latest fence which'll then recursively forward operations to chained fences.
This change also ends up mandating a move away from `FenceCycleDependency` as it would prevent fences from concurrently locking the same resources which is required for chaining to work as two fences being chained fundamentally means they're locking the same resources. The `AtomicForwardList` is therefore used as the new container.
An implementation of a singly-linked list with atomic access to allow for lock-free access semantics, it eliminates the requirement for a mutex which can introduce additional consideration for synchronization.
Resources on the GPU can be fairly convoluted and involve overlaps which can lead to the same GPU resources being utilized with different views, we previously utilized fences to lock resources to prevent concurrent access but this was overly harsh as it would block usage of resources till GPU completion of the commands associated with a resource.
Fences have now been replaced with locks but locks run into the issue of being per-view and therefore to add a common object for tracking usage the concept of "tags" was introduced to track a single context so locks can be skipped if they're from the same context. This is important to prevent a deadlock when locking a resource which has been already locked from the current context with a different view.
We do not want to allow saving of user data on unsigned builds as they don't have a stable signature and will not properly handle reinstallation. This can lead to a situation where the user has to resort to complex techniques to completely uninstall the package such as ADB or calling into PM directly.
We currently present all frames synchronously on the thread that calls into SurfaceFlinger functions, this is unoptimal as it doesn't match guest behavior which can lead to delaying the guest from working on the next frame. This commit queuing up frames to non-blocking and handles all waiting then presenting the frame on a dedicated thread.
We utilize `pthread_setname_np` to set the thread names but didn't check for any errors which resulted in the `Skyline-Choreographer` and `ChannelCmdFifo` not having proper names as they exceeded the 16 character limit on thread names for the pthread function. This has now been fixed by changing the names and introducing error checking to invocations of this function.
All our normal alignment functions are designed to only handle power of 2 (`POT`) multiples as we only align or check alignment to `POT` multiples but there are cases where this is not possible and we deal with `NPOT` multiples which is why this function is required.
We waited on the host GPU after `Execute` but this isn't optimal as it causes a major stall on the CPU which can lead to several adverse effects such as downclocking by the governor and losing the opportunity to work in parallel with the GPU.
This has now been fixed by splitting `Execute`'s functionality into two functions: `Submit` and `SubmitWithFlush` which both execute all nodes and submit the resulting command buffer to the GPU but flushing will wait on the GPU to complete while the non-flush variant will not wait and work ahead of the GPU.
We need move-assignment semantics to viably utilize these objects as class members, they cannot be replaced without move-assign (or copy-assign but that is undesirable here). This commit fixes that by introducing a move assignment operator to them while making the `slot` a pointer which has the necessary nullability semantics.
This change lets items get the updated position of their view holder in the adapter. Fixes an issue where the position of items was not updated after being removed from a `SelectableGenericAdapter`.
This preference launches `GpuDriverActivity` for managing custom gpu drivers. When the device has an incompatible GPU, the preference will be disabled and greyed out.
The activity adds the following functionalities:
* Lists installed drivers
* Allows the user to install new drivers, or remove installed ones
* Allows the user to select the driver that will be used by the emulator
At some point we will call Submit within draws or constant buffer updates, to avoid any infinite recursion mark draw/cbuf pending as false before performing any operation
The previous name was chosen as an afterthought and didn't clearly indicate what the purpose of the class is. We needed a separate, simple class without delegates members (like PreferenceSettings), so that its fields can be easily accessed via JNI to get settings values from native code.
The `Settings` class now has a pure virtual `Update` method, and uses inheritance over template specialization for platform-specific behavior override.
A `Setting` delegate class has been introduced, holding the raw value of the setting and adding support for registering callbacks to that setting. Callbacks will then be called when the value of that setting changes.
As a result of this, raw setting values have been made accessible through pointer dereference semantics.
SharedPreferences will be partially swapped out in the future to support per-game settings. In the meantime, make it clear from which class settings are coming from.
