lkml.org 
[lkml]   [2021]   [Jan]   [18]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
From
SubjectRe: [PATCH v1 5/5] driver core: Set fw_devlink=on by default
Hi Geert,

On 2021-01-18 17:39, Geert Uytterhoeven wrote:
> Hi Saravana,
>
> On Fri, Dec 18, 2020 at 4:34 AM Saravana Kannan <saravanak@google.com>
> wrote:
>> Cyclic dependencies in some firmware was one of the last remaining
>> reasons fw_devlink=on couldn't be set by default. Now that cyclic
>> dependencies don't block probing, set fw_devlink=on by default.
>>
>> Setting fw_devlink=on by default brings a bunch of benefits
>> (currently,
>> only for systems with device tree firmware):
>> * Significantly cuts down deferred probes.
>> * Device probe is effectively attempted in graph order.
>> * Makes it much easier to load drivers as modules without having to
>> worry about functional dependencies between modules (depmod is still
>> needed for symbol dependencies).
>>
>> If this patch prevents some devices from probing, it's very likely due
>> to the system having one or more device drivers that "probe"/set up a
>> device (DT node with compatible property) without creating a struct
>> device for it. If we hit such cases, the device drivers need to be
>> fixed so that they populate struct devices and probe them like normal
>> device drivers so that the driver core is aware of the devices and
>> their
>> status. See [1] for an example of such a case.
>>
>> [1] -
>> https://lore.kernel.org/lkml/CAGETcx9PiX==mLxB9PO8Myyk6u2vhPVwTMsA5NkD-ywH5xhusw@mail.gmail.com/
>> Signed-off-by: Saravana Kannan <saravanak@google.com>
>
> Shimoda-san reported that next-20210111 and later fail to boot
> on Renesas R-Car Gen3 platforms. No output is seen, unless earlycon
> is enabled.
>
> I have bisected this to commit e590474768f1cc04 ("driver core: Set
> fw_devlink=on by default").

There is a tentative patch from Saravana here[1], which works around
some issues on my RK3399 platform, and it'd be interesting to find
out whether that helps on your system.

Thanks,

M.

[1]
https://lore.kernel.org/r/20210116011412.3211292-1-saravanak@google.com
--
Jazz is not dead. It just smells funny...

\
 
 \ /
  Last update: 2021-01-18 19:02    [W:0.346 / U:0.256 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site