Re: [Bugfix] x86, irq: Fix a regression caused by commit b5dc8e6c21e7

Thomas Gleixner
2015-08-17T21:12:20Z

On Sun, 9 Aug 2015, Jiang Liu wrote:

> Alex Deucher, Mark Rustad and Alexander Holler reported a regression
> with the latest v4.2-rc4 kernel, which breaks some SATA controllers.
> With multi-MSI capable SATA controllers, only the first port works,
> all other ports times out when executing SATA commands. This regression
> bisects to 52f518a3a7c2 ("x86/MSI: Use hierarchical irqdomains to manage
> MSI interrupts"), but it's not the root cause, it just triggers a bug
> caused by b5dc8e6c21e7 ("x86/irq: Use hierarchical irqdomain to manage
> CPU interrupt vectors").
>
> With this patch applied, the affected SATA controllers work as expected.

This changelog including the subject line is horrible.

1) The subject line should describe the change in a short and precise form

x86/irq: Fix a regression caused by commit b5dc8e6c21e7

fits the short category, but completely fails to be precise. It's
not interesting for the subject line which commit caused the
problem and whether it's a regression or not. We want a to see a
proper description of the change itself.

2) The changelog should describe the bug itself.

... but it's not the root cause, it just triggers a bug caused by
b5dc8e6c21e7 ("x86/irq: Use hierarchical irqdomain to manage CPU
interrupt vectors").

does not tell what the actual bug in the code is.

3) The changelog should describe the solution.

With this patch applied, the affected SATA controllers work as
expected.

is describing the desired effect of the change, but not the change
itself.

Thanks,

tglx