On 07/02/2018 at 16:47:00 +0100, Alexandre Belloni wrote: > > >> > I really don't think anyone is using that but I don't really know much > > >> > about x86 and the specification this may be part of. > > >> > > > >> > I see the info may be used in drivers/video/fbdev/ and > > >> > drivers/platform/x86/thinkpad_acpi.c > > >> > > >> The thinkpad_acpi driver seems to look at some other bytes > > >> in the nvram, which have a platform specific meaning. > > >> > > > > > > Yeah, I was more concerned that they need drivers/char/nvram.c for > > > nvram_read_byte so we can't simply remove the driver. > > > > Ok, so the procfs interface may be obsolete, but we still need an > > interface into the CMOS NVRAM data. > > > > Actually, I just found > https://unix.stackexchange.com/questions/331419/is-dev-nvram-dangerous-to-write-to > > So it seems to have real values for some people (even if they are > wrong). > > That also points to https://sourceforge.net/projects/nvram-wakeup/ but I > don't think it is necessary. The RTC driver should be able to wakeup an > x86 platform. > > All the other uses of /dev/nvram I could find with a simple google > search (i.e. saving and restoring CMOS settings) could just use > /sys/class/rtc/rtc0/device/nvram >
Ok, the chromeos guys are using it for verified boot it seems: https://chromium.googlesource.com/chromiumos/platform/vboot_reference I'm wondering whether they really care about the checksum though. -- Alexandre Belloni, Bootlin (formerly Free Electrons) Embedded Linux and Kernel engineering http://bootlin.com
