Here is the second version for handling non-standard LED status in VMD domains. There are significant differences this time around: First, after discussing the original proposal, we decided that we can't support allowing user space have direct write access to config space. This potentially breaks the PCIe Slot Control command sequence, so patch 1/2 provides an alternate sysfs attention setter/getter in addition to ignoring the indicators for standard usage. Second, I've since learned that there is no such VID/DID list I can use in order to flag this quirk. The exact same devices with the quirk behave differently when used outside a VMD domain. Since this quirk behavior is specific to the VMD PCIe domain, the new approach is to set options specific to domains as pci_dev's are being added. Since patch 2/2 requires changes to x86 common code, I've added the x86 maintainers in addition to PCI, and I'll re-summarize what this feature/quirk is about: This came from wanting a simple SGPIO-like LED management solution for PCIe SSDs. The Intel group who made this hardware, not considering the more broad impact on standarization, chose to reuse the hot plug serial SMBus in the Intel CPUs (aka VPP) that already carried the Slot Control register bits out of the CPU. This hardware implementation therefore re-purposes the Slot Control's Attention Indicator Control and Power Indicator Control of the PCI Express Capabilities structure. Rather than using the PCIe standard interpretation, this hardware uses IBPI (International Blinking Pattern Interpretation). One side affect is that the Attention and Power indicator presence bits in the Slot Capabilities structures must remain enabled due to how the hardware is wired. This would confuse the pciehp driver since it would incorrectly (albeit understandably) assume how to control these capabilities. So this patch series has to tell pciehp to keep away from controlling these indicators and provide a way for the user to set them instead. This quirky behavior consideration is only required for the current generation of this hardware. Future generations will use standards compliance as being pursued within the PCI-SIG and NVMe-MI standards bodies. Keith Busch (2): pciehp: Let user control LED status x86/vmd: Add PCI domain specific LED option arch/x86/include/asm/pci.h | 14 ++++++++++++++ arch/x86/pci/common.c | 7 +++++++ arch/x86/pci/vmd.c | 1 + drivers/pci/hotplug/pciehp.h | 1 + drivers/pci/hotplug/pciehp_core.c | 26 ++++++++++++++++++++++++++ drivers/pci/hotplug/pciehp_hpc.c | 6 +++++- include/linux/pci.h | 1 + 7 files changed, 55 insertions(+), 1 deletion(-) -- 2.7.2 -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
