Re: [PATCH v4 0/5] ARM: at91: fix irq_pm_install_action WARNING

[Boris Brezillon <boris.brezillon@free-electrons.com>]

Hi Thomas,

Any chance this could go in the next kernel release ?
More and more people are complaining about this backtrace :-/.

Regards,

Boris

On Thu, 29 Jan 2015 11:33:35 +0100
Boris Brezillon <boris.brezillon@free-electrons.com> wrote:
> Commit cab303be91dc47942bc25de33dc1140123540800 [1] introduced a WARN_ON
> test which triggers a WARNING backtrace on at91 platforms.
> While this WARN_ON is absolutely necessary to warn users that they should
> not mix request with and without IRQF_NO_SUSPEND flags on shared IRQs,
> there is no easy way to solve this issue on at91 platforms.
> 
> The main reason is that the init timer is often using a shared irq line
> and thus request this irq with IRQF_NO_SUSPEND flag set, while other
> peripherals request the same irq line without this flag.
> 
> As suggested by Thomas, the first 3 patches of this series add a dumb
> demultiplexer irqchip implementation.
> This demuxer registers to a source interrupt and then forwards all received
> interrupts to its children (it they are enabled).
> 
> The last two patches rework at91 DTs and config to make use of this dumb
> demuxer implementation.
> 
> Rob, I know you were not in favor of exposing this in the DT but we really
> need to quickly a solution: more and more people complain about this warning.
> If you see a better way to handle this case please share it.
> 
> Best Regards,
> 
> Boris
> 
> Changes since v3:
>  - replace dumb by virt
> 
> Changes since v2:
>  - removed unneeded dumb demux flags passed to irq_alloc_dumb_demux_chip
>  - set nested lockdep class for all requested irqs
>  - add some explanation to the DT binding doc
>  - change the compatible string to clearly show that this chip is purely
>    virtual
>  - added dumb demuxer to all at91 impacted SoCs
> 
> Changes since v1:
>  - went for an dumb irq demuxer approach instead of trying to fix the
>    current shared irq code
> 
> Boris Brezillon (5):
>   genirq: Authorize chained handlers to remain disabled when initialized
>   irqchip: add virtual demultiplexer implementation
>   irqchip: Add DT binding doc for the virtual irq demuxer chip
>   ARM: at91/dt: select VIRT_IRQ_DEMUX for all at91 SoCs
>   ARM: at91/dt: define a virtual irq demultiplexer chip connected on
>     irq1
> 
>  .../bindings/interrupt-controller/dumb-demux.txt   |  41 ++++++
>  arch/arm/boot/dts/at91rm9200.dtsi                  |  20 ++-
>  arch/arm/boot/dts/at91sam9260.dtsi                 |  26 +++-
>  arch/arm/boot/dts/at91sam9261.dtsi                 |  26 +++-
>  arch/arm/boot/dts/at91sam9263.dtsi                 |  29 ++++-
>  arch/arm/boot/dts/at91sam9g45.dtsi                 |  29 ++++-
>  arch/arm/boot/dts/at91sam9n12.dtsi                 |  25 +++-
>  arch/arm/boot/dts/at91sam9rl.dtsi                  |  29 ++++-
>  arch/arm/boot/dts/at91sam9x5.dtsi                  |  26 +++-
>  arch/arm/mach-at91/Kconfig                         |   2 +
>  drivers/irqchip/Kconfig                            |   4 +
>  drivers/irqchip/Makefile                           |   1 +
>  drivers/irqchip/irq-virt-demux.c                   |  72 +++++++++++
>  include/linux/irq.h                                |  64 +++++++++-
>  include/linux/irqdomain.h                          |   1 +
>  kernel/irq/Kconfig                                 |   5 +
>  kernel/irq/Makefile                                |   1 +
>  kernel/irq/chip.c                                  |  53 +++++++-
>  kernel/irq/handle.c                                |  31 ++++-
>  kernel/irq/internals.h                             |   3 +
>  kernel/irq/irqdomain.c                             |   2 +-
>  kernel/irq/msi.c                                   |   3 +-
>  kernel/irq/virt-demux-chip.c                       | 140 +++++++++++++++++++++
>  23 files changed, 580 insertions(+), 53 deletions(-)
>  create mode 100644 Documentation/devicetree/bindings/interrupt-controller/dumb-demux.txt
>  create mode 100644 drivers/irqchip/irq-virt-demux.c
>  create mode 100644 kernel/irq/virt-demux-chip.c
> 



-- 
Boris Brezillon, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com