On 1/23/24 16:59, Johan Hovold wrote:
On Wed, Jan 03, 2024 at 01:36:08PM +0100, Konrad Dybcio wrote:
Commit b43f7ddc2b7a ("power: supply: qcom_battmgr: Register the power
supplies after PDR is up") moved the devm_power_supply_register() calls
so that the power supply devices are not registered before we go through
the entire initialization sequence (power up the ADSP remote processor,
wait for it to come online, coordinate with userspace..).
Some firmware versions (e.g. on SM8550) seem to leave battmgr at least
partly initialized when exiting the bootloader and loading Linux. Check
if the power supply devices are registered before consuming the battmgr
notifications.
So this clearly was not tested properly as the offending commit breaks
both the Lenovo ThinkPad X13s and the SC8280XP CRD.
I spent some time this afternoon tracking down and considering the best
way to address this before I checked lore and found this proposed fix
(why was I not CCed?).
I didn't give the offending commit a spin on the laptops, as I simply
assumed the interface is generic enough to behave similarly across the
platforms. With this, I didn't imagine the DSP firmwares aren't unloaded
on these..
[...]
+ if (!battmgr->bat_psy)
+ return;
This is not a proper fix. You register 3-4 class devices and only check
one. Even if your checked the last one, there's no locking or barriers
in place to prevent this from breaking.
Deferred registration of the class devices also risks missing
notifications as you'll be spending time on registration after the
service has gone live.
I'm sure all of this can be handled but as it is non-trivial and the
motivation for the offending commit is questionable to begin with, I
suggest reverting for now.
I'll send a revert for Sebastian to consider.
What you're saying is valid, but a "battery" device is always expected
to be present. If devm_power_supply_register fails, things would go very
south very fast anyway. I personally don't see this being a terribly bad
fix, but I'm open to different propositions.
Konrad
