[U-Boot] distro: add more efi dtb prefixes

[Alexander Graf]

On 02.12.18 23:07, Heinrich Schuchardt wrote:
> On 12/2/18 10:47 PM, Alexander Graf wrote:
>>
>>
>> On 16.07.18 20:06, Heinrich Schuchardt wrote:
>>> On 06/14/2018 10:46 PM, Guillaume GARDET wrote:
>>>> As used on some distro, such as openSUSE.
>>>> Signed-off-by: Guillaume GARDET <guillaume.gardet at free.fr>
>>>>
>>>> Cc: Tom Rini <trini at konsulko.com>
>>>> ---
>>>>  include/config_distro_bootcmd.h | 3 ++-
>>>>  1 file changed, 2 insertions(+), 1 deletion(-)
>>>>
>>>> diff --git a/include/config_distro_bootcmd.h b/include/config_distro_bootcmd.h
>>>> index d672e8ebe6..ad4c7a78f1 100644
>>>> --- a/include/config_distro_bootcmd.h
>>>> +++ b/include/config_distro_bootcmd.h
>>>> @@ -141,7 +141,8 @@
>>>>  		"load ${devtype} ${devnum}:${distro_bootpart} "           \
>>>>  			"${fdt_addr_r} ${prefix}${efi_fdtfile}\0"         \
>>>>  	\
>>>> -	"efi_dtb_prefixes=/ /dtb/ /dtb/current/\0"                        \
>>>> +	"efi_dtb_prefixes=/ /dtb/ /dtb/current/ "                         \
>>>> +		"/boot/ /boot/dtb/ /boot/dtb/current/\0"                  \
>>>
>>> I prefer programming against standards and not against whatever is out
>>> in the wild.
>>>
>>> Could you, please, indicate according to which standard you think that
>>> the dtb should be found in directory /boot/dtb of the EFI partition.
>>
>> In openSUSE we have 2 hacks:
>>
>>   1) Search for the DTB on the second partition always, not the active one
>>
>>   2) Search for the DTB in additional paths (this patch)
>>
>> The reason being that we do not want to copy the DTB to the EFI boot
>> partition, but instead just provide it in an easily accessible /boot/dtb
>> directory on the root partition that gets updated by RPM.
>>
>> Now, I personally think that this is a pretty distro specific hack. I am
>> not sure how much more of a hack it is than searching for a DTB file at
>> all though :).
>>
>> So I'm personally not terribly opposed to pulling this in upstream.
>> /boot/dtb is as little standardized as /dtb/ or /dtb/current/ is.
>>
>>
>> Alex
>>
> Adding more and more paths slows down the boot process. So this should
> be avoided.
> 
> Isn't boot.scr meant to do the distribution specific stuff?
> 
> I think it is sufficient to find the boot.scr file and let it do its
> job. Ubuntu and Debian are already working like this. Does Suse not have
> the capability to install a boot.scr?

We try not to, since I really don't want to get into the boot.scr
business again. I also ideally don't want to load any DT at all from the
kernel - in my opinion U-Boot should just provide an up-to-date one and
we're all happy.

So yes, I'm perfectly fine with leaving that in the openSUSE tree too.

I want to make sure all that kernel DT nonsense does a slow death anyway :).


Alex