[U-Boot] [PATCH v2 2/3] efi_loader: enumerate disk devices every time

[Alexander Graf]

On 13.12.18 08:58, AKASHI Takahiro wrote:
> Heinrich,
> 
> On Tue, Dec 11, 2018 at 08:55:41PM +0100, Heinrich Schuchardt wrote:
>> On 11/15/18 5:58 AM, AKASHI Takahiro wrote:
>>> Currently, efi_init_obj_list() scan disk devices only once, and never
>>> change a list of efi disk devices. This will possibly result in failing
>>> to find a removable storage which may be added later on. See [1].
>>>
>>> In this patch, called is efi_disk_update() which is responsible for
>>> re-scanning UCLASS_BLK devices and removing/adding efi disks if necessary.
>>>
>>> For example,
>>>
>>> => efishell devices
>>> Scanning disk pci_mmc.blk...
>>> Found 3 disks
>>> Device Name
>>> ============================================
>>> /VenHw(e61d73b9-a384-4acc-aeab-82e828f3628b)
>>> /VenHw(e61d73b9-a384-4acc-aeab-82e828f3628b)/SD(0)/SD(0)
>>> /VenHw(e61d73b9-a384-4acc-aeab-82e828f3628b)/SD(0)/SD(0)/HD(2,MBR,0x086246ba,0x40800,0x3f800)
>>> => usb start
>>> starting USB...
>>> USB0:   USB EHCI 1.00
>>> scanning bus 0 for devices... 3 USB Device(s) found
>>>        scanning usb for storage devices... 1 Storage Device(s) found
>>> => efishell devices
>>> Scanning disk usb_mass_storage.lun0...
>>> Device Name
>>> ============================================
>>> /VenHw(e61d73b9-a384-4acc-aeab-82e828f3628b)
>>> /VenHw(e61d73b9-a384-4acc-aeab-82e828f3628b)/SD(0)/SD(0)
>>> /VenHw(e61d73b9-a384-4acc-aeab-82e828f3628b)/SD(0)/SD(0)/HD(2,MBR,0x086246ba,0x40800,0x3f800)
>>> /VenHw(e61d73b9-a384-4acc-aeab-82e828f3628b)/USBClass(0,0,9,0,1)/USBClass(46f4,1,0,0,0)/HD(1,0x01,0,0x40,0x14fe4c)
>>>
>>> Without this patch, the last device, USB mass storage, won't show up.
>>>
>>> [1] https://lists.denx.de/pipermail/u-boot/2018-October/345307.html
>>>
>>> Signed-off-by: AKASHI Takahiro <takahiro.akashi at linaro.org>
>>
>> Why should we try to fix something in the EFI subsystems that goes wrong
>> in the handling of device enumeration.
> 
> No.
> This is a natural result from how efi disks are currently implemented on u-boot.
> Do you want to totally re-write/re-implement efi disks?

Could we just make this event based for now? Call a hook from the
storage dm subsystem when a new u-boot block device gets created to
issue a sync of that in the efi subsystem?

That hook would obviously only do something (or get registered?) when
the efi object stack is initialized.

The long term goal IMHO should still be though to just merge DM and EFI
objects. But we're still waiting on the deprecation of non-DM devices
for that.


Alex