[PATCH 4/7] wined3d: Avoid using destroyed context.

[Henri Verbeet]

On 3 October 2016 at 17:27, Józef Kucia <joseph.kucia at gmail.com> wrote:
> 03.10.2016 3:47 PM "Henri Verbeet" <hverbeet at gmail.com>:
>> I think it may be harder to fix than this. If state_unbind_resources()
>> can end up destroying the (primary) swapchain, it's not safe to call
>> context_acquire() afterwards. Which means it's unsafe to unload
>> resources or even unload a different SRV. The reason destroying the
>> RTVs is currently safe, is that we unloaded resources earlier, so
>> releasing the references to the resources for those views shouldn't
>> acquire a context to destroy e.g. the GL texture again, but that's
>> already more fragile than I'd like. Perhaps we should just delay
>> destroying the context until leaving the last level.
>
> I think this fix is correct. The device keeps a reference to the implicit
> swapchain. The implicit swapchain is destroyed just before leaving from
> wined3d_device_uninit_3d() so it should be safe to call context_acquire().
>
> This problem occurs only for additional swapchains and that's why it happens
> only in test_swapchain_flip().

You're probably right. (Although that's not to say the code wouldn't
benefit from being a little more robust. I think it's hard to reason
about.) Is state_unbind_shaders() required? I assume it's because
unbinding the shaders needs to happen before destroying the shader
backend, but would delaying the context_acquire() call until after the
wine_rb_clear() call also work?