DolphinQt: Fix the panic alert deadlock, GPU thread edition

The fix in ef77872 worked for panic alerts from
the CPU thread, but there were still problems with
panic alerts from the GPU thread in dual core mode.
This change attempts to fix those.
This commit is contained in:
JosJuice
2020-04-25 00:26:51 +02:00
parent 07fd17445c
commit 3367e5e026
5 changed files with 59 additions and 21 deletions

View File

@ -41,20 +41,31 @@ static bool QtMsgAlertHandler(const char* caption, const char* text, bool yes_no
Common::MsgType style)
{
const bool called_from_cpu_thread = Core::IsCPUThread();
const bool called_from_gpu_thread = Core::IsGPUThread();
std::optional<bool> r = RunOnObject(QApplication::instance(), [&] {
Common::ScopeGuard scope_guard(&Core::UndeclareAsCPUThread);
Common::ScopeGuard cpu_scope_guard(&Core::UndeclareAsCPUThread);
Common::ScopeGuard gpu_scope_guard(&Core::UndeclareAsGPUThread);
if (!called_from_cpu_thread)
cpu_scope_guard.Dismiss();
if (!called_from_gpu_thread)
gpu_scope_guard.Dismiss();
if (called_from_cpu_thread)
{
// Temporarily declare this as the CPU thread to avoid getting a deadlock if any DolphinQt
// code calls RunAsCPUThread while the CPU thread is blocked on this function returning.
// Notably, if the panic alert steals focus from RenderWidget, Host::SetRenderFocus gets
// called, which can attempt to use RunAsCPUThread to get us out of exclusive fullscreen.
// If the panic alert that we are about to create steals the focus from RenderWidget,
// Host::SetRenderFocus gets called, which can attempt to use RunAsCPUThread to get us out
// of exclusive fullscreen. If we don't declare ourselves as the CPU thread, RunAsCPUThread
// calls PauseAndLock, which causes a deadlock if the CPU thread is waiting on us returning.
Core::DeclareAsCPUThread();
}
else
if (called_from_gpu_thread)
{
scope_guard.Dismiss();
// We also need to avoid getting a deadlock when the GPU thread is waiting on us returning.
// Declaring ourselves as the GPU thread does not alter the behavior of RunAsCPUThread or
// PauseAndLock, but it does make Host::SetRenderFocus not call RunAsCPUThread.
Core::DeclareAsGPUThread();
}
ModalMessageBox message_box(QApplication::activeWindow(), Qt::ApplicationModal);