14 DAY TRIAL // Owners of Apple iPhones that are also running Windows 7 on computers with Intel chipsets can find that the devices connected to the machine via USB freeze up. Microsoft indicates that additional single USB bulk storage devices are affected. The Redmond company only mentioned the iPhone among the devices that users reported issues about, and underlined that the number of products similarly impacted by this problem is limited. [admark=1] Single USB bulk storage devices, iPhone included, can become completely unresponsive when connected to Windows 7 Home Premium, Professional or Ultimate.
“This issue may occur when the following conditions are true: the computer has a chipset from the Intel 5 Series or the Intel 3400 Series families of Intel chipsets and the USB device has pending control and bulk traffic,” Microsoft explained.
According to the software giant, at fault is the Platform Controller Hub (PCH) which, in the conditions mentioned above, cannot decide how to prioritize traffic type. “Therefore, the port that is associated with the USB device stops responding. This issue occurs when the processor is in the C0 power state for a long time. For example, Cx states are not enabled, or system traffic prevents the system from leaving the C0 power state. If Cx states are enabled, the device may recover a short time later,” Microsoft stated.
The problem described above has nothing to do with Microsoft or with Windows 7 for that matter. Users are advised to contact Intel and to grab a system BIOS update from the CPU vendor. “This issue only affects a limited number of USB devices. The issue only occurs if the USB device driver programs the Nak Count Reload bits that are defined in the EHCI Specification for USB Rev 1.0 to 0,” the Redmond company added.