Messages in this thread |  | | Date | Tue, 4 Oct 2016 16:23:46 +0200 (CEST) | From | Thomas Gleixner <> | Subject | Re: [PATCH 3/3] Revert "ACPI,PCI,IRQ: remove SCI penalize function" |
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On Tue, 4 Oct 2016, Sinan Kaya wrote:
> On 10/4/2016 3:23 AM, Thomas Gleixner wrote: > > On Sat, 1 Oct 2016, Sinan Kaya wrote: > > > >> This reverts commit 9e5ed6d1fb87 ("ACPI,PCI,IRQ: remove SCI penalize > >> function"). SCI penalty API was replaced by the runtime penalty calculation > >> based on the value of acpi_gbl_FADT.sci_interrupt. > > > > This does more than only reverting said commit .... > > The SCI function was removed in two steps (first refactor and then remove). > I was trying to do the revert at one step. I can divide into two if it makes > it better
No one step is fine. But this wants to be documented in the changelog.
> >> acpi_gbl_FADT.sci_interrupt type does not get updated at the right time > >> for some platforms and results in incorrect penalty assignment for PCI > >> IRQs as irq_get_trigger_type returns the wrong type. > > > > And the obvious question is: Why does irq_get_trigger_type() return the > > wrong type? > > Here is some history: > > I now remember that Bjorn indicated the race condition possibility in this thread > here. > > https://lkml.org/lkml/2016/3/8/640
> My understanding is that register_gsi function delivers the IRQ found in > the ACPI table to the interrupt controller driver. Penalties are > calculated before a link object is enabled to find out which interrupt > has the least number of users. By the time penalties are calculated, the > IRQ is not registered yet and it returns the wrong type.
Ok.
> > > > What's the root cause of this problem? Your changelog does not tell > > anything. > > If you are OK with the above description, I can add this to the commit message.
Yes please.
Thanks,
tglx
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