Re: (subset) [PATCH v2 0/7] Really implement Qualcomm LAB/IBB regulators

From: AngeloGioacchino Del Regno
Date: Fri Jan 15 2021 - 14:16:40 EST


Il 15/01/21 19:19, Mark Brown ha scritto:
On Wed, 13 Jan 2021 20:42:07 +0100, AngeloGioacchino Del Regno wrote:
Okay, the title may be a little "aggressive"? However, the qcom-labibb
driver wasn't really .. doing much.
The current form of this driver is only taking care of enabling or
disabling the regulators, which is pretty useless if they were not
pre-set from the bootloader, which sets them only if continuous
splash is enabled.
Moreover, some bootloaders are setting a higher voltage and/or a higher
current limit compared to what's actually required by the attached
hardware (which is, in 99.9% of the cases, a display) and this produces
a higher power consumption, higher heat output and a risk of actually
burning the display if kept up for a very long time: for example, this
is true on at least some Sony Xperia MSM8998 (Yoshino platform) and
especially on some Sony Xperia SDM845 (Tama platform) smartphones.

[...]

Applied to

https://git.kernel.org/pub/scm/linux/kernel/git/broonie/regulator.git for-next

Thanks!

[1/7] regulator: qcom-labibb: Implement voltage selector ops
commit: dd582369c6c1f39ec475af6191a934f3e57fda35

All being well this means that it will be integrated into the linux-next
tree (usually sometime in the next 24 hours) and sent to Linus during
the next merge window (or sooner if it is a bug fix), however if
problems are discovered then the patch may be dropped or reverted.

You may get further e-mails resulting from automated or manual testing
and review of the tree, please engage with people reporting problems and
send followup patches addressing any issues that are reported if needed.

If any updates are required or you are submitting further changes they
should be sent as incremental updates against current git, existing
patches will not be replaced.

Please add any relevant lists and maintainers to the CCs when replying
to this mail.

Thanks,
Mark


Hello Mark,

Thanks for applying the commit, however, I feel like reminding you that setting voltage on this regulator without setting a current limit is really unsafe (at least, from many, many experiments) so, to ensure the entire safety of this code and the hardware that's attached to these regulators you should, please, either apply the entire series, or nothing.

My concerns are only about keeping LAB and IBB safe for everyone's hardware.

Thank you again
-- Angelo