On Fri, Mar 09, 2018 at 11:20:53AM +0100, Jean Delvare wrote: > > + else if (size & 0x8000) > > + bytes = (u64)(size & 0x7fff) << 10; > > + else if (size != 0x7fff) > > + bytes = (u64)size << 20; > > + else > > + bytes = (u64)get_unaligned((u32 *)&d[0x1C]) << 20; > > + > > + dmi_memdev[nr].size = bytes; > > I'm curious, do you really need to know the amount of memory to the > byte? The SMBIOS specification itself does not support granularity > under 1 kB. I would be very surprised if any machine running Linux > today has memory modules under 1 MB. If storing in MB you wouldn't need > a u64... I got side-tracked reading the standard with the ancient ways used to report size back in the day when kilobytes was a plausible unit. So I wrote code that covers all the crazy cases. Persistant DIMMs have sizes measured in gigabytes. I should stop worrying about "0" vs. "fffffff" and just treat the old cases as errors and simplify the code to be: u32 mbytes; if (size == 0 || (size & 0x8000)) mbytes = 0; if (size != 0x7fff) mbytes = size; else mbytes = get_unaligned((u32 *)&d[0x1C]); Then I can use 32-bit throughout this and patch 5. Thanks for the review. -Tony -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
