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Groups > linux.kernel > #1360461
| From | Geert Uytterhoeven <geert@linux-m68k.org> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: [PATCH 04/15] irqchip/gic: WARN if setting the interrupt type fails |
| Date | 2016-03-18 10:30 +0100 |
| Message-ID | <rdYTg-3Ff-11@gated-at.bofh.it> (permalink) |
| References | (1 earlier) <rdH63-6P-35@gated-at.bofh.it> <rdHz3-gE-5@gated-at.bofh.it> <rdHIJ-zS-5@gated-at.bofh.it> <rdHSq-Dd-9@gated-at.bofh.it> <rdIYa-1i1-15@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
On Thu, Mar 17, 2016 at 5:20 PM, Jon Hunter <jonathanh@nvidia.com> wrote:
> On 17/03/16 15:18, Jason Cooper wrote:
>> On Thu, Mar 17, 2016 at 03:04:01PM +0000, Jon Hunter wrote:
>>> On 17/03/16 14:51, Thomas Gleixner wrote:
>>>> On Thu, 17 Mar 2016, Jon Hunter wrote:
>>>>> Setting the interrupt type for private peripheral interrupts (PPIs) may
>>>>> not be supported by a given GIC because it is IMPLEMENTATION DEFINED
>>>>> whether this is allowed. There is no way to know if setting the type is
>>>>> supported for a given GIC and so the value written is read back to
>>>>> verify it matches the desired configuration. If it does not match then
>>>>> an error is return.
>>>>>
>>>>> There are cases where the interrupt configuration read from firmware
>>>>> (such as a device-tree blob), has been incorrect and hence
>>>>> gic_configure_irq() has returned an error. This error has gone
>>>>> undetected because the error code returned was ignored but the interrupt
>>>>> still worked fine because the configuration for the interrupt could not
>>>>> be overwritten.
>>>>>
>>>>> Given that this has done undetected and we should only fail to set the
>>>>> type for PPIs whose configuration cannot be changed anyway, don't return
>>>>> an error and simply WARN if this fails. This will allows us to fix up any
>>>>> places in the kernel where we should be checking the return status and
>>>>> maintain back compatibility with firmware images that may have incorrect
>>>>> interrupt configurations.
>>>>
>>>> Though silently returning 0 is really the wrong thing to do. You can add the
>>>> warn, but why do you want to return success?
>>>
>>> Yes that would be the correct thing to do I agree. However, the problem
>>> is that if we do this, then after the patch "irqdomain: Don't set type
>>> when mapping an IRQ" is applied, we may break interrupts for some
>>> existing device-tree binaries that have bad configuration (such as omap4
>>> and tegra20/30 ... see patches 1 and 2) that have gone unnoticed. So it
>>> is a back compatibility issue.
Indeed (also for sh73a0 and r8a7779).
>> This sounds like a textbook case for adding a boolean dt property. If
>> "can-set-ppi-type" is absent (old DT blobs and new blobs without the
>> ability), warn and return zero. If it's present, the driver can set the
>> type, returning errors as encountered.
>
> True. However, if we did have this "can-set-ppi-type" property set for a
> device, it really should never fail (unless someone specified it
> incorrectly). So I am trying to understand the value in adding a new DT
> property.
Do we really want to add properties that basically indicate that a description
in DT is correct?
Alternatively, it can be fixed in the kernel in a DT quirk (if SoC == xxx then
fix TWD).
> Please note that gic_configure_irq() never used to return an error and
> only when adding support for setting the type of PPIs was this added.
> However, given that this has gone unnoticed and does not have a real
> functional impact on the device behaviour, I wonder now if this function
> should return an error? Yes, ideally, it should, but does it still make
> sense?
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
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[PATCH 00/15] Add support for Tegra210 AGIC Jon Hunter <jonathanh@nvidia.com> - 2016-03-17 15:30 +0100
[PATCH 05/15] irqchip: Mask the non-type/sense bits when translating an IRQ Jon Hunter <jonathanh@nvidia.com> - 2016-03-17 15:30 +0100
[PATCH 09/15] irqchip/gic: Don't initialise chip if mapping IO space fails Jon Hunter <jonathanh@nvidia.com> - 2016-03-17 15:30 +0100
[PATCH 02/15] ARM: OMAP: Correct interrupt type for ARM TWD Jon Hunter <jonathanh@nvidia.com> - 2016-03-17 15:30 +0100
Re: [PATCH 02/15] ARM: OMAP: Correct interrupt type for ARM TWD Grygorii Strashko <grygorii.strashko@ti.com> - 2016-03-18 16:50 +0100
Re: [PATCH 02/15] ARM: OMAP: Correct interrupt type for ARM TWD Jon Hunter <jonathanh@nvidia.com> - 2016-03-29 16:10 +0200
Re: [PATCH 02/15] ARM: OMAP: Correct interrupt type for ARM TWD Tony Lindgren <tony@atomide.com> - 2016-03-30 23:30 +0200
[PATCH 10/15] irqchip/gic: Remove static irq_chip definition for eoimode1 Jon Hunter <jonathanh@nvidia.com> - 2016-03-17 15:30 +0100
Re: [PATCH 10/15] irqchip/gic: Remove static irq_chip definition for eoimode1 Linus Walleij <linus.walleij@linaro.org> - 2016-03-22 12:50 +0100
[PATCH 08/15] genirq: Add runtime power management support for IRQ chips Jon Hunter <jonathanh@nvidia.com> - 2016-03-17 15:30 +0100
Re: [PATCH 08/15] genirq: Add runtime power management support for IRQ chips Marc Zyngier <marc.zyngier@arm.com> - 2016-03-17 16:10 +0100
Re: [PATCH 08/15] genirq: Add runtime power management support for IRQ chips Jon Hunter <jonathanh@nvidia.com> - 2016-03-17 16:20 +0100
Re: [PATCH 08/15] genirq: Add runtime power management support for IRQ chips Marc Zyngier <marc.zyngier@arm.com> - 2016-03-17 16:30 +0100
Re: [PATCH 08/15] genirq: Add runtime power management support for IRQ chips Linus Walleij <linus.walleij@linaro.org> - 2016-03-22 12:50 +0100
Re: [PATCH 08/15] genirq: Add runtime power management support for IRQ chips Thomas Gleixner <tglx@linutronix.de> - 2016-03-17 16:10 +0100
Re: [PATCH 08/15] genirq: Add runtime power management support for IRQ chips Jon Hunter <jonathanh@nvidia.com> - 2016-03-17 16:50 +0100
Re: [PATCH 08/15] genirq: Add runtime power management support for IRQ chips Grygorii Strashko <grygorii.strashko@ti.com> - 2016-03-18 12:20 +0100
Re: [PATCH 08/15] genirq: Add runtime power management support for IRQ chips Jon Hunter <jonathanh@nvidia.com> - 2016-03-18 13:30 +0100
Re: [PATCH 08/15] genirq: Add runtime power management support for IRQ chips Grygorii Strashko <grygorii.strashko@ti.com> - 2016-03-18 15:30 +0100
Re: [PATCH 08/15] genirq: Add runtime power management support for IRQ chips Jon Hunter <jonathanh@nvidia.com> - 2016-03-18 15:50 +0100
Re: [PATCH 08/15] genirq: Add runtime power management support for IRQ chips Jon Hunter <jonathanh@nvidia.com> - 2016-03-18 16:00 +0100
Re: [PATCH 08/15] genirq: Add runtime power management support for IRQ chips Grygorii Strashko <grygorii.strashko@ti.com> - 2016-03-18 19:00 +0100
Re: [PATCH 08/15] genirq: Add runtime power management support for IRQ chips Jon Hunter <jonathanh@nvidia.com> - 2016-03-21 11:10 +0100
[PATCH 12/15] irqchip/gic: Pass GIC pointer to save/restore functions Jon Hunter <jonathanh@nvidia.com> - 2016-03-17 15:30 +0100
[PATCH 13/15] irqchip/gic: Prepare for adding platform driver Jon Hunter <jonathanh@nvidia.com> - 2016-03-17 15:30 +0100
Re: [PATCH 13/15] irqchip/gic: Prepare for adding platform driver Geert Uytterhoeven <geert@linux-m68k.org> - 2016-03-29 15:10 +0200
Re: [PATCH 13/15] irqchip/gic: Prepare for adding platform driver Jon Hunter <jonathanh@nvidia.com> - 2016-03-29 16:00 +0200
[PATCH 04/15] irqchip/gic: WARN if setting the interrupt type fails Jon Hunter <jonathanh@nvidia.com> - 2016-03-17 15:30 +0100
Re: [PATCH 04/15] irqchip/gic: WARN if setting the interrupt type fails Thomas Gleixner <tglx@linutronix.de> - 2016-03-17 16:00 +0100
Re: [PATCH 04/15] irqchip/gic: WARN if setting the interrupt type fails Jon Hunter <jonathanh@nvidia.com> - 2016-03-17 16:10 +0100
Re: [PATCH 04/15] irqchip/gic: WARN if setting the interrupt type fails Jason Cooper <jason@lakedaemon.net> - 2016-03-17 16:20 +0100
Re: [PATCH 04/15] irqchip/gic: WARN if setting the interrupt type fails Jon Hunter <jonathanh@nvidia.com> - 2016-03-17 17:30 +0100
Re: [PATCH 04/15] irqchip/gic: WARN if setting the interrupt type fails Geert Uytterhoeven <geert@linux-m68k.org> - 2016-03-18 10:30 +0100
Re: [PATCH 04/15] irqchip/gic: WARN if setting the interrupt type fails Jon Hunter <jonathanh@nvidia.com> - 2016-03-18 11:00 +0100
Re: [PATCH 04/15] irqchip/gic: WARN if setting the interrupt type fails Geert Uytterhoeven <geert@linux-m68k.org> - 2016-03-18 11:30 +0100
[PATCH 03/15] irqchip/gic: Don't unnecessarily write the IRQ configuration Jon Hunter <jonathanh@nvidia.com> - 2016-03-17 15:30 +0100
[PATCH 14/15] dt-bindings: arm-gic: Drop 'clock-names' from binding document Jon Hunter <jonathanh@nvidia.com> - 2016-03-17 15:30 +0100
Re: [PATCH 14/15] dt-bindings: arm-gic: Drop 'clock-names' from binding document Rob Herring <robh+dt@kernel.org> - 2016-03-17 21:20 +0100
Re: [PATCH 14/15] dt-bindings: arm-gic: Drop 'clock-names' from binding document Jon Hunter <jonathanh@nvidia.com> - 2016-03-18 09:40 +0100
Re: [PATCH 14/15] dt-bindings: arm-gic: Drop 'clock-names' from binding document Geert Uytterhoeven <geert@linux-m68k.org> - 2016-03-18 10:20 +0100
Re: [PATCH 14/15] dt-bindings: arm-gic: Drop 'clock-names' from binding document Jon Hunter <jonathanh@nvidia.com> - 2016-03-18 11:20 +0100
Re: [PATCH 14/15] dt-bindings: arm-gic: Drop 'clock-names' from binding document Geert Uytterhoeven <geert@linux-m68k.org> - 2016-03-18 12:00 +0100
Re: [PATCH 14/15] dt-bindings: arm-gic: Drop 'clock-names' from binding document Jon Hunter <jonathanh@nvidia.com> - 2016-03-18 12:00 +0100
Re: [PATCH 14/15] dt-bindings: arm-gic: Drop 'clock-names' from binding document Geert Uytterhoeven <geert@linux-m68k.org> - 2016-03-18 13:10 +0100
Re: [PATCH 14/15] dt-bindings: arm-gic: Drop 'clock-names' from binding document Grygorii Strashko <grygorii.strashko@ti.com> - 2016-03-18 13:50 +0100
Re: [PATCH 14/15] dt-bindings: arm-gic: Drop 'clock-names' from binding document Geert Uytterhoeven <geert@linux-m68k.org> - 2016-03-18 14:10 +0100
Re: [PATCH 14/15] dt-bindings: arm-gic: Drop 'clock-names' from binding document Grygorii Strashko <grygorii.strashko@ti.com> - 2016-03-18 19:40 +0100
Re: [PATCH 14/15] dt-bindings: arm-gic: Drop 'clock-names' from binding document Jon Hunter <jonathanh@nvidia.com> - 2016-03-18 13:50 +0100
[PATCH 11/15] irqchip/gic: Return an error if GIC initialisation fails Jon Hunter <jonathanh@nvidia.com> - 2016-03-17 15:30 +0100
[PATCH 15/15] irqchip/gic: Add support for tegra AGIC interrupt controller Jon Hunter <jonathanh@nvidia.com> - 2016-03-17 15:30 +0100
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