On 10-4-23 下午7:37, Samuel Thibault wrote: > Da Zheng, le Fri 23 Apr 2010 14:51:22 +0800, a écrit : >> They are not just one or two variables. They are an array of structure >> variables. Should I define all fields of the structure with volatile >> qualifier? > > You can qualify the whole structure > >> It's strange. The Linux driver doesn't do so but it definitely works in the >> Linux kernel. > > It does (or should do): such pointers have the __io qualifier. I checked the code of e1000 again. The data for MMIO is qualified by __iomem, but the data in the transmission or receiving queues (which are accessed by DMA) doesn't have __iomem or any similar qualifiers. I guess the data in the transmission queue is very unlikely to be in registers when the driver accesses it.
Zheng Da
