On 8 June 2018 at 11:51, Feng Tang <feng.tang@xxxxxxxxx> wrote: > When doing some boot time optimization for an eMMC rootfs NUCs, > we found the rootfs may spend around 100 microseconds waiting > for eMMC card to be initialized, then the rootfs could be > mounted. > [ 1.216561] Waiting for root device /dev/mmcblk1p1... > [ 1.289262] mmc1: new HS400 MMC card at address 0001 > [ 1.289667] mmcblk1: mmc1:0001 R1J56L 14.7 GiB > [ 1.289772] mmcblk1boot0: mmc1:0001 R1J56L partition 1 8.00 MiB > [ 1.289869] mmcblk1boot1: mmc1:0001 R1J56L partition 2 8.00 MiB > [ 1.289967] mmcblk1rpmb: mmc1:0001 R1J56L partition 3 4.00 MiB > [ 1.292798] mmcblk1: p1 p2 p3 > [ 1.300576] EXT4-fs (mmcblk1p1): couldn't mount as ext3 due to feature incompatibilities > [ 1.300912] EXT4-fs (mmcblk1p1): couldn't mount as ext2 due to feature incompatibilities > > And this is a common problem for smartphones, tablets, embedded > devices and automotive products. This patch will make the eMMC/SD > card start initializing earlier, by changing its order in drivers/Makefile. > > On our platform, the waiting for eMMC card is almost eliminated with the patch, > which is critical to boot time. I am wondering what kernel version you are running here. There have been some changes to the mmc initialization path, which perhaps can help. > > Signed-off-by: Feng Tang <feng.tang@xxxxxxxxx> > --- > drivers/Makefile | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/drivers/Makefile b/drivers/Makefile > index 24cd47014657..c473afd3c688 100644 > --- a/drivers/Makefile > +++ b/drivers/Makefile > @@ -50,6 +50,9 @@ obj-$(CONFIG_REGULATOR) += regulator/ > # reset controllers early, since gpu drivers might rely on them to initialize > obj-$(CONFIG_RESET_CONTROLLER) += reset/ > > +# put mmc early as many morden devices use emm/sd card as rootfs storage > +obj-y += mmc/ > + Your suggested approach isn't really a solution, as it may work for your particular case but not for everybody else. > # tty/ comes before char/ so that the VT console is the boot-time > # default. > obj-y += tty/ > @@ -128,7 +131,6 @@ obj-$(CONFIG_EISA) += eisa/ > obj-$(CONFIG_PM_OPP) += opp/ > obj-$(CONFIG_CPU_FREQ) += cpufreq/ > obj-$(CONFIG_CPU_IDLE) += cpuidle/ > -obj-y += mmc/ > obj-$(CONFIG_MEMSTICK) += memstick/ > obj-$(CONFIG_NEW_LEDS) += leds/ > obj-$(CONFIG_INFINIBAND) += infiniband/ > -- > 2.14.1 > Kind regards Uffe -- To unsubscribe from this list: send the line "unsubscribe linux-mmc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
