From mboxrd@z Thu Jan 1 00:00:00 1970 From: AKASHI Takahiro Date: Fri, 17 Jan 2020 15:12:41 +0900 Subject: fat: handle Windows formatted partition (thru USB Mass Storage) In-Reply-To: References: <4983915a-d95c-5b4d-8b9d-ebc2cbb45837@gmx.de> <20200115001258.GG28530@linaro.org> <20200116020108.GH28530@linaro.org> <7a1d7387-82d2-e425-953e-aae95eda30d3@gmx.de> Message-ID: <20200117061240.GO28530@linaro.org> List-Id: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: u-boot@lists.denx.de On Thu, Jan 16, 2020 at 10:31:49PM +0200, Andy Shevchenko wrote: > On Thu, Jan 16, 2020 at 9:20 PM Heinrich Schuchardt wrote: > > On 1/16/20 11:39 AM, Andy Shevchenko wrote: > > > > > >>> Obviously U-Boot's fat code cannot handle it. > > >> > > >> So precisely, U-Boot cannot handle nested partition( table)s? > > > > > > Seems so. We need to be able to supply the partition number we would > > > like to open, something like > > > cmd [[:[:]]] > > > otherwise it will require some (error prone) heuristics to understand > > > which one user would like to use. > > > > > > > I have formatted a USB stick Windows 10. > > That is *not* the case I'm describing. > > Maybe I described it wrong. Let me try again. > > Prerequisites: > - the board with U-Boot and installed Linux OS on eMMC > - g_multi module in Linux OS that shares *one of the eMMC partitions* > (pay attention here) as a disk to Windows host I also misunderstood your assumption above; You are developing a linux-based USB gadget for Windows (10)? > Now, when you format that exposed disk (which is actually a partition > on eMMC!) in Windows, you will get nested partitioning. So why do you want to access *that* partition from U-Boot on the board? I don't think it is a common case. -Takahiro Akashi > P.S. I can easily reproduce this on real device with latest U-Boot. > U-Boot has obvious issue with recognizing such disks. > > -- > With Best Regards, > Andy Shevchenko