On Sun, 2015-11-29 at 22:26 -0800, Andy Lutomirski wrote: > My laptop has /sys/devices/platform/e820_pmem and autoloads all the > nvdimm infrastructure. While it would be really cool if my laptop > had > pmem, that's a bit of a pipe dream right now. (Even if it did have > it, this laptop is brand new -- it should use NFIT, not e820_pmem.) > > Could we move the iomem_resource loop from drivers/nvdimm/e820.c to > arch/x86/kernel/pmem.c and actually list the iomem resources the > standard way as resources belonging to the platform device? That > would match accepted practice, and it would keep the grossly > x86-specific part of the driver in arch/x86. Then we could further > tweak it to skip creating the platform device at all if there are no > resources, and we'd avoid needlessly loading the module. > > I'd do this myself, except that my lovely machine that *does* support > e820 pmem has been repurposed, so testing on a machine that actually > supports this turd is awkward for me.
This works for me... 8<--- Subject: libnvdimm, e820: skip module loading when no type-12 From: Dan Williams <[email protected]> If there are no persistent memory ranges present then don't bother creating the platform device. Otherwise, it loads the full libnvdimm sub-system only to discover no resources present. Reported-by: Andy Lutomirski <[email protected]> Signed-off-by: Dan Williams <[email protected]> --- arch/x86/kernel/pmem.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) diff --git a/arch/x86/kernel/pmem.c b/arch/x86/kernel/pmem.c index 4f00b63d7ff3..14415aff1813 100644 --- a/arch/x86/kernel/pmem.c +++ b/arch/x86/kernel/pmem.c @@ -4,10 +4,22 @@ */ #include <linux/platform_device.h> #include <linux/module.h> +#include <linux/ioport.h> + +static int found(u64 start, u64 end, void *data) +{ + return 1; +} static __init int register_e820_pmem(void) { + char *pmem = "Persistent Memory (legacy)"; struct platform_device *pdev; + int rc; + + rc = walk_iomem_res(pmem, IORESOURCE_MEM, 0, -1, NULL, found); + if (rc <= 0) + return 0; /* * See drivers/nvdimm/e820.c for the implementation, this is-- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
