On Mon, 24 May 2021 15:36:51 +0100,
Marek Behún [off-list ref] wrote:

On Fri, 07 May 2021 10:08:18 +0100
Marc Zyngier [off-list ref] wrote:

quoted

On Thu, 06 May 2021 16:31:26 +0100,
Pali Rohár [off-list ref] wrote:

quoted

This name is visible in /proc/interrupts file and for better reading it
should have at most 8 characters. Also there is no need to allocate this
name dynamically, since there is only one PCIe controller on Armada 37xx.
This aligns with how the MSI irq_chip in this driver names it's interrupt
("advk-MSI").  

And *because* the name is visible in /proc/interrupts, it has become
an ABI, and cannot be changed anymore.

We had the exact same issue with Tegra this merge window as I
accidentally changed "Tegra" to "tegra", resulting in userspace
programs failing find stuff in /proc/interrupts.

Please keep the name as is, no matter how ugly it is.

Hmm, I am 99% sure that for the A3720 platform this ABI change would not
affect anybody. And it does make the driver's irq names confusing.
Can't we really do anything here?

No, this is final. Show anything in /proc/*, maintain it forever. We
already went there with the bogomips crap showing up in
/proc/cpuinfo. There is no way you can know what userspace does, and
the best course of action is not to change things for some dubious
value of "nicer" or "less confusing".

Note that there were suggestions from some people to completely remove
this driver due to the many problems it has which Pali is trying to
solve. But if the driver was removed and then later introduced again
without these problems, the new version would use the "advk-INT" IRQ
name...

No, you would have to keep the *exact same output*. Userspace doesn't
know about drivers, and expect things in /proc to be stable.

Frankly, there are more important things to do than to worry about the
shape of /proc/interrupts. And if we could change it, I'd simply get
rid of it (you really should look at it on a system that has ~200
CPUs...).

Thanks,

	M.

-- 
Without deviation from the norm, progress is not possible.

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