On 4/7/2017 1:25 PM, James Bottomley wrote: >> The right thing was to either call __raw_writel/__raw_readl or >> write_relaxed/read_relaxed for multi-arch compatibility. > writeX_relaxed and thus your patch is definitely wrong. The reason is > that we have two ordering domains: the CPU and the Bus. wmb forces > ordering in the CPU domain but not the bus domain. writeX originally > forced ordering in the bus domain but not the CPU domain, but since the > raw primitives I think it now orders in both and writeX_relaxed orders > in neither domain, so your patch would currently eliminate the bus > ordering. Yeah, that's why I recommended to remove the wmb() with a follow up instead of using the relaxed with a follow up. writel already guarantees ordering for both cpu and bus. we don't need additional wmb() -- Sinan Kaya Qualcomm Datacenter Technologies, Inc. as an affiliate of Qualcomm Technologies, Inc. Qualcomm Technologies, Inc. is a member of the Code Aurora Forum, a Linux Foundation Collaborative Project.
