Thread (17 messages) 17 messages, 2 authors, 2017-07-12

cpufreq: frequency scaling spec in DT node

From: viresh.kumar@linaro.org (Viresh Kumar)
Date: 2017-07-12 03:41:50
Also in: linux-pm

On 11-07-17, 13:09, Mason wrote:
I apologize for being unclear.

What I meant is that the bootloader originally set the max frequency
to 1206 MHz. The OPP table in DTS was written based on that value.

Later, someone changed the bootloader code to set a slightly higher
max frequency. When I flashed the new bootloader on my board, the
OPP table no longer matches the actual frequency.

But I am not notified when bootloader authors change max frequencies,
which is why I wrote "changed the max freq behind my back".

Again, sorry for the confusing statements.

(The bootloader is not DT-aware, so it leaves the DT untouched.)
Here we go. Finally I have understood what the problem you are facing is :)
And yes, it was really not clear to me until now. I though that someone just
changed the max in DT and that's making things go bad :)

Anyway, how does the bootloader control the max frequency? For the boards I
worked on, its just a PLL that the kernel needs to set and kernel can choose to
program it the way it wants to irrespective of the way bootloader has worked on
it.
Maybe this is the real issue that needs to be addressed,
rather than the symptoms that turn up later because of
the root issue.
Sure, I just need a bit more of input from you :)

-- 
viresh
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