Hi Greg, Thanks for the prompt review. On Tue, Aug 14, 2018 at 09:40:41AM +0200, Greg Kroah-Hartman wrote: > On Tue, Aug 14, 2018 at 03:38:10PM +0800, Feng Tang wrote: > > Hi Greg, > > > > On Tue, Aug 14, 2018 at 09:18:34AM +0200, Greg Kroah-Hartman wrote: > > > On Tue, Aug 14, 2018 at 02:39:59PM +0800, Feng Tang wrote: > > > > Hi Greg, Ulf > > > > > > > > Could you help to review this? many thanks! > > > > > > Review what? I see no patch here. And why would I need to review a mmc > > > patch in the middle of the merge window? > > > > > > totally confused, > > > > Sorry for the confusion! I didn't noticed the 4.19 merge window. > > > > The patch was originally posted in June, and has gone through some > > review discussions with mmc maintainers, my last mail was trying > > to keep some discussion info. > > Ok, then why ask me? I'm not the mmc maintainer. The reason is this patch not only touches the mmc, but also affects many other subsystems in drivers/ as the init order is changed. And the get_maintainer.pl shows you are the first suggested reviewer for changes to drivers/Makefile :) > > > The original patch is: > > ----- > > > > >From 1514c7d56e887ace37466dded09bc43f2a4c9a4a Mon Sep 17 00:00:00 2001 > > From: Feng Tang <feng.tang@xxxxxxxxx> > > Date: Fri, 8 Jun 2018 17:10:30 +0800 > > Subject: [PATCH] mmc: Move the mmc driver init earlier > > > > 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. And it should benefit other non-x86 platforms > > which see the similar waiting for emmc rootfs. > > > > 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 > > Spelling error :) Will change it. > > > +obj-y += mmc/ > > + > > # tty/ comes before char/ so that the VT console is the boot-time > > # default. > > obj-y += tty/ > > Everyone wants to be first. Watch out if you try to put stuff before > tty, you have to be very careful. There are sd serial devices, right? As the eMMC/SD card initialization takes quite some time, the SDHCI host controller's module init function will quickly return, while leaving a worker to do the real card detection/initialization, so other subsystems should not be blocked. And yes, it is safer to move it after tty/ > > Anyway, nothing we can do now until after 4.19-rc1 is out. Understood, will send v2 after the merge window. Thanks again. - Feng
