# tIOPCIDeviceResetTypes ``` typedef enum tIOPCIDeviceResetTypes : unsigned int { ... } tIOPCIDeviceResetTypes; ``` ## Overview ``` This will issue a hot reset from its upstream bridge by setting the secondary bus reset bit in the bridge's control register. ``` ``` specific function exists. ``` ``` specific function exists. Upon completion, the device is unusable until the caller requests reset with type kIOPCIDeviceResetTypeWarmResetEnable. This type facilitates the generation of a cold reset, i.e. by removing power before using kIOPCIDeviceResetTypeWarmResetDisable and re-applying it before using kIOPCIDeviceResetTypeWarmResetEnable. ``` ``` (e.g. deassert PERST#). See kIOPCIDeviceResetTypeWarmResetDisable for more details. ``` ## Topics ### Enumeration Cases [`kIOPCIDeviceResetTypeFunctionReset`](/documentation/PCIDriverKit/tIOPCIDeviceResetTypes/kIOPCIDeviceResetTypeFunctionReset) [`kIOPCIDeviceResetTypeHotReset`](/documentation/PCIDriverKit/tIOPCIDeviceResetTypes/kIOPCIDeviceResetTypeHotReset) [`kIOPCIDeviceResetTypeWarmReset`](/documentation/PCIDriverKit/tIOPCIDeviceResetTypes/kIOPCIDeviceResetTypeWarmReset) [`kIOPCIDeviceResetTypeWarmResetDisable`](/documentation/PCIDriverKit/tIOPCIDeviceResetTypes/kIOPCIDeviceResetTypeWarmResetDisable) [`kIOPCIDeviceResetTypeWarmResetEnable`](/documentation/PCIDriverKit/tIOPCIDeviceResetTypes/kIOPCIDeviceResetTypeWarmResetEnable) --- Copyright © 2026 Apple Inc. All rights reserved. | [Terms of Use](https://www.apple.com/legal/internet-services/terms/site.html) | [Privacy Policy](https://www.apple.com/privacy/privacy-policy)