24.02.2020 19:33, Karel Zak пишет: > On Wed, Feb 19, 2020 at 09:59:54AM -0700, Stephen Warren wrote: >> On 2/19/20 9:27 AM, Christoph Hellwig wrote: >>> On Wed, Feb 19, 2020 at 07:23:39PM +0300, Dmitry Osipenko wrote: >>>> The gpt_sector=<sector> causes the GPT partition search to look at the >>>> specified sector for a valid GPT header if the GPT is not found at the >>>> beginning or the end of block device. >>>> >>>> In particular this is needed for NVIDIA Tegra consumer-grade Android >>>> devices in order to make them usable with the upstream kernel because >>>> these devices use a proprietary / closed-source partition table format >>>> for the EMMC and it's impossible to change the partition's format. Luckily >>>> there is a GPT table in addition to the proprietary table, which is placed >>>> in uncommon location of the EMMC storage and bootloader passes the >>>> location to kernel using "gpt gpt_sector=<sector>" cmdline parameters. >>>> >>>> This patch is based on the original work done by Colin Cross for the >>>> downstream Android kernel. >>> >>> I don't think a magic command line is the way to go. The best would be >>> to reverse-engineer the proprietary partition table format. If that is >>> too hard we can at least key off the odd GPT location based of it's >>> magic number. > > +1 > >> I thought that the backup GPT was always present in the standard location; > > If they have proprietary stuff on begin of the device and valid backup > GPT at the end of the device then designer of this junk is crazy, because > many GPT fdisk-like tools will try to recover from the backup header and > overwrite the unknown (invalid) stuff at the begin of the device... It's a problem created by vendor, but these devices are assumed to run Android-only. So it's not really that bad :)
