差異處

這裏顯示兩個版本的差異處。

--- cpp:linux_kernel:smbus_controller [2016/01/21 21:53]
tony [Problem]
+++ cpp:linux_kernel:smbus_controller [2023/06/25 09:48]
@@ 行 1: / 行 1: @@
-{{tag>linux}}
-====== 在UEFI-aware OS上遇到的SMBus Controller問題 ======
-===== Problem =====
-最近遇到在UEFI-aware的Windows上，SMBus Controller沒被enable的情況，這是發生在Wellsburg的PCH chip。可以透過取得SMBus Controller的PCI Configuration的0x04，確認bit 0(IO space)與bit 1(Memory space)是否為0得知。然而卻一直無法得知這算是BIOS還是OS Driver該去enable的。\\
-\\
-目前知道並非所有的linux diver都會去enable這個register，而Wellsburg使用到的i2c-i801則會去enable。可以參考[[http://lxr.free-electrons.com/source/drivers/i2c/busses/i2c-i801.c|i2c-i801.c]]的i801_probe，裡面會使用到[[http://lxr.free-electrons.com/source/drivers/pci/pci.c#L1467|pcim_enable_device]]。接著可以trace到以下的code:
-<code cpp>
-  * pci_enable_device - Initialize device before it's used by a driver.
-  * @dev: PCI device to be initialized
-  *
-  *  Initialize device before it's used by a driver. Ask low-level code
-  *  to enable I/O and memory. Wake up the device if it was suspended.
-  *  Beware, this function can fail.
-  *
-  *  Note we don't actually enable the device many times if we call
-  *  this function repeatedly (we just increment the count).
-  */
-int pci_enable_device(struct pci_dev *dev)
-{
-         return pci_enable_device_flags(dev, IORESOURCE_MEM | IORESOURCE_IO);
-}
-</code>
-至於到底是BIOS要去enable，還是OS driver要去enable，等我找到資料再補充。
-===== Reference =====
-  * [[http://lxr.free-electrons.com/source/drivers/i2c/busses/i2c-i801.c|i2c-i801.c]]