On Tue, Aug 24, 2021 at 07:06:18PM +0300, Dmitry Osipenko wrote: > 24.08.2021 13:38, Michał Mirosław пишет: > > On Tue, Aug 24, 2021 at 01:40:02AM +0200, Michał Mirosław wrote: > >> On Sat, Aug 21, 2021 at 08:27:15PM +0300, Dmitry Osipenko wrote: > >>> 21.08.2021 01:41, Michał Mirosław пишет: > >>>> On Thu, Aug 19, 2021 at 01:19:15AM +0300, Dmitry Osipenko wrote: > >>>>> This series adds the most minimal EFI partition support for NVIDIA Tegra > >>>>> consumer devices, like Android tablets and game consoles, making theirs > >>>>> eMMC accessible out-of-the-box using downstream bootloader and mainline > >>>>> Linux kernel. eMMC now works on Acer A500 tablet and Ouya game console > >>>>> that are already well supported in mainline and internal storage is the > >>>>> only biggest thing left to support. > >>>> [...] > >>>> > >>>> Could we provide the GPT sector via DT? As I understand this is for > >>>> non-removable eMMC storage. It would remove the need for a cap bit and > >>>> hardcoded calculations instead just checking if DT node of the controller > >>>> contains a magic entry with a number. > >>> > >>> The same device model usually comes in different flavors that have a > >>> different eMMC unit and size. So no, it can't be hardcoded in DT. > >> > >> I see. I was thinking how to avoid of going the whole way and creating > >> another controller capability (since this is going to be core code) - > >> could this workaround be enabled just by a boolean DT property at > >> controller's node instead? Or do we expect non-DT platforms to be > >> similarly broken? > > > > Rewording my concern: I believe that this is platform's and not > > a controller's misfeature, so the controller driver feels like wrong > > place fix. That's why I'd prefer that the enable came from the DT > > and not from driver's code. > > The alternative GPT entry requires user to add 'gpt' argument to > kernel's cmdline. If board already uses proper alternative GPT entry at > the last sector, then nothing changed for that board. > > The case where board uses 'gpt' cmdline + it had stale GPT entry at the > special location used by Android devices and chance that now suddenly > that GPT entry will pop up is close to zero. > > All old partition table entries should be erased on reparation. If it > wasn't done, then it's not a kernel's problem, it's much more a user's > problem. Even though kernel could help that poor user if will be really > needed. > > There is no reason to over-engineer unless somebody will tell that it > broke the very special board. Neither of currently supported boards > should require more quirks. Hence, why bother? You could drop patch 4 from v7 if you checked DT boolean property instead of adding a capability in patch 3. (Patch 4 would be replaced by DT changes for relevant boards.) Best Regards Michał Mirosław
