This patch moves the firmware loading (read firmware from disk and load
it into the device SRAM) from pci_probe time to the first network
interface open time. There are two reasons for doing this:
1. To support kernel buildin iwlwifi drivers. Because kernel initializes
network devices subsystem before hard disk and SATA subsystem, it is
impossible to get the firmware image from hard disk in the PCI probe
handler. Thus delaying the firmware loading into the network
interface open time is the way to go. Note, we only read the firmware
image from hard disk the first time the interface is open. After this
is succeeded, we cache the firmware image into the host memory. This
is a performance gain when user open and close the interface multiple
times and is necessary for device suspend and resume.
2. For better power saving. When the iwlwifi modules are loaded (or
buildin the kernel) but the wireless network interface is not being
used, it is a good practice the wireless device consumes as less
power as possible. Unloading the firmware from the wireless device
and unregister the driver's interrupt handler in the network
interface close handler provides users a way to achieve this. User
space network configuration tools (i.e NetworkManager) can also
contribute here when it detects a wired cable is connected and
close the wireless interface automatically.
This patch also includes the pci_save/restore_state() fixed by Ian Schram
upon the first version.
Signed-off-by: Zhu Yi <yi.zhu@intel.com>
Signed-off-by: Ian Schram <ischram@telenet.be>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
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