Re: [PATCH v2 05/21] ARM: tegra: clock: Disable clocks left on by bootloader

Colin Cross
2011-02-21T03:43:40Z

On Sun, Feb 20, 2011 at 4:40 PM, Olof Johansson <olof@lixom.net> wrote:
> Hi,
>
> On Sat, Feb 19, 2011 at 2:25 PM, Colin Cross <ccross@android.com> wrote:
>> Adds CONFIG_TEGRA_DISABLE_BOOTLOADER_CLOCKS that iterates
>> through all clocks, disabling any for which the refcount
>> is 0 but the clock init detected the bootloader left the
>> clock on.
>
>
> I would argue that any kernel functionality that relies on clocks
> being left on my bootloader is buggy, and/or should at least have
> those clocks enabled in the static clock tables for the boards in
> question, since it creates an undocumented dependency on firmware.
>
> I would prefer if it disabled the clocks by default (after warning),
> but that there was a runtime way to override while debugging (i.e. add
> a bootarg 'keep_fwclocks' or similar to keep the firmware-enabled
> clocks running and just warn about them).

That was the plan, but since many of the drivers are missing I didn't
want to enable it by default yet. However, it turns out the problems
I was seeing at boot from this patch were actually due to a bug in the
clock code causing the cpu clock to be disabled for clocks that have
no disable. I will drop this patch, and post a separate series after
these that fixes the bug and turns off clocks by default, with a
runtime argument like you suggested.