From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jisheng Zhang Subject: Re: [PATCH 0/3] Patches to allow consistent mmc / mmcblk numbering Date: Fri, 29 Apr 2016 10:18:36 +0800 Message-ID: <20160429101836.060ad087@xhacker> References: <1461884805-29466-1-git-send-email-dianders@chromium.org> Mime-Version: 1.0 Content-Type: text/plain; charset="US-ASCII" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1461884805-29466-1-git-send-email-dianders-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org> Sender: devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Douglas Anderson , ulf.hansson-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org, jh80.chung-Sze3O3UU22JBDgjK7y7TUQ@public.gmane.org Cc: shawn.lin-TNX95d0MmH7DzftRWevZcw@public.gmane.org, adrian.hunter-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org, stefan-XLVq0VzYD2Y@public.gmane.org, linux-mmc-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, computersforpeace-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org, dmitry.torokhov-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org, mark.rutland-5wv7dgnIgG8@public.gmane.org, vbyravarasu-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org, justin.wang-lxIno14LUO0EEoCn2XhGlw@public.gmane.org, ksumrall-z5hGa2qSFaRBDgjK7y7TUQ@public.gmane.org, lars-Qo5EllUWu/uELgA04lAiVw@public.gmane.org, dtor-F7+t8E8rja9g9hUCZPvPmw@public.gmane.org, jonathanh-DDmLM1+adcrQT0dZR+AlfA@public.gmane.org, huangtao-TNX95d0MmH7DzftRWevZcw@public.gmane.org, devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, pawel.moll-5wv7dgnIgG8@public.gmane.org, ijc+devicetree-KcIKpvwj1kUDXYZnReoRVg@public.gmane.org, galak-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org, lporzio-AL4WhLSQfzjQT0dZR+AlfA@public.gmane.org, robh+dt-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, chuanxiao.dong-ral2JQCrhuEAvxtiuMwx3w@public.gmane.org, chaotian.jing-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org, sergei.shtylyov-M4DtvfQ/ZS1MRgGoP+s0PdBPR1lH4CV8@public.gmane.org, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, sudeep.holla-5wv7dgnIgG8@public.gmane.org List-Id: devicetree@vger.kernel.org Dear Douglas, On Thu, 28 Apr 2016 16:06:42 -0700 Douglas Anderson wrote: > This series picks patches from various different places to produce what > I consider the best solution to getting consistent mmc and mmcblk > ordering. > > Why consistent ordering and why not just use UUIDs? IMHO consistent > ordering solves a few different problems: > > 1. For poor, feeble-minded humans like me, have sane numbering for > devices helps a lot. When grepping through dmesg it's terribly handy > if a given SDMMC device has a consistent number. I know that I can > do "dmesg | grep mmc0" or "dmesg | grep mmcblk0" to find info about > the eMMC. I know that I can do "dmesg | grep mmc1" to find info > about the SD card slot. I don't want it to matter which one probed > first, I don't want it to matter if I'm working on a variant of the > hardware that has the SD card slot disabled, and I don't want to care > what my boot device was. Worrying about what device number I got > increases my cognitive load. > > 2. There are cases where it's not trivially easy during development to > use the UUID. Specifically I work a lot with coreboot / depthcharge > as a BIOS. When configured properly, that BIOS has a nice feature to > allow you to fetch the kernel and kernel command line from TFTP by > pressing Ctrl-N. In this particular case the BIOS doesn't actually > know which disk I'd like for my root filesystem, so it's not so easy > for it to put the right UUID into the command line. For this > purpose, knowing that "mmcblk0" will always refer to eMMC is handy. > > > Jaehoon Chung (1): > Documentation: mmc: Document mmc aliases > > Stefan Agner (2): > mmc: read mmc alias from device tree > mmc: use SD/MMC host ID for block device name ID We also need this feature. Thanks so much for upstreaming the series. Jisheng > > Documentation/devicetree/bindings/mmc/mmc.txt | 11 +++++++++++ > drivers/mmc/card/block.c | 3 ++- > drivers/mmc/core/host.c | 25 ++++++++++++++++++++----- > 3 files changed, 33 insertions(+), 6 deletions(-) > -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html