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    Subject[PATCH 47/49] Documentation: irq: Change documents related to IRQF_DISABLED
    Date
    IRQF_DISABLED is a NOOP now, place where suggest to use this
    flag also doesn't make sense any more.

    Signed-off-by: Yong Zhang <yong.zhang0@gmail.com>
    Cc: Bjorn Helgaas <bhelgaas@google.com>
    ---
    Documentation/PCI/MSI-HOWTO.txt | 21 ---------------------
    Documentation/scsi/ncr53c8xx.txt | 3 ++-
    Documentation/scsi/tmscsim.txt | 4 ++--
    3 files changed, 4 insertions(+), 24 deletions(-)

    diff --git a/Documentation/PCI/MSI-HOWTO.txt b/Documentation/PCI/MSI-HOWTO.txt
    index 53e6fca..b3f514d 100644
    --- a/Documentation/PCI/MSI-HOWTO.txt
    +++ b/Documentation/PCI/MSI-HOWTO.txt
    @@ -255,27 +255,6 @@ as many vectors for MSI as it could for MSI-X. On some platforms, MSI
    interrupts must all be targeted at the same set of CPUs whereas MSI-X
    interrupts can all be targeted at different CPUs.

    -4.5.2 Spinlocks
    -
    -Most device drivers have a per-device spinlock which is taken in the
    -interrupt handler. With pin-based interrupts or a single MSI, it is not
    -necessary to disable interrupts (Linux guarantees the same interrupt will
    -not be re-entered). If a device uses multiple interrupts, the driver
    -must disable interrupts while the lock is held. If the device sends
    -a different interrupt, the driver will deadlock trying to recursively
    -acquire the spinlock.
    -
    -There are two solutions. The first is to take the lock with
    -spin_lock_irqsave() or spin_lock_irq() (see
    -Documentation/DocBook/kernel-locking). The second is to specify
    -IRQF_DISABLED to request_irq() so that the kernel runs the entire
    -interrupt routine with interrupts disabled.
    -
    -If your MSI interrupt routine does not hold the lock for the whole time
    -it is running, the first solution may be best. The second solution is
    -normally preferred as it avoids making two transitions from interrupt
    -disabled to enabled and back again.
    -
    4.6 How to tell whether MSI/MSI-X is enabled on a device

    Using 'lspci -v' (as root) may show some devices with "MSI", "Message
    diff --git a/Documentation/scsi/ncr53c8xx.txt b/Documentation/scsi/ncr53c8xx.txt
    index cda5f8f..6cb311b 100644
    --- a/Documentation/scsi/ncr53c8xx.txt
    +++ b/Documentation/scsi/ncr53c8xx.txt
    @@ -786,7 +786,8 @@ port address 0x1400.
    irqm:1 same as initial settings (assumed BIOS settings)
    irqm:2 always totem pole
    irqm:0x10 driver will not use IRQF_SHARED flag when requesting irq
    - irqm:0x20 driver will not use IRQF_DISABLED flag when requesting irq
    + irqm:0x20 driver will not use IRQF_DISABLED flag when requesting
    + irq (only useful for linux-2.6.34 and earlier)

    (Bits 0x10 and 0x20 can be combined with hardware irq mode option)

    diff --git a/Documentation/scsi/tmscsim.txt b/Documentation/scsi/tmscsim.txt
    index 61c0531..1dee219 100644
    --- a/Documentation/scsi/tmscsim.txt
    +++ b/Documentation/scsi/tmscsim.txt
    @@ -108,8 +108,8 @@ MHz PCI bus works for me, though, but I don't recommend using higher clocks
    than the 33.33 MHz being in the PCI spec.

    If you want to share the IRQ with another device and the driver refuses to
    -do so, you might succeed with changing the DC390_IRQ type in tmscsim.c to
    -IRQF_SHARED | IRQF_DISABLED.
    +do so, you should find out what's the mismatch between the shared IRQs,
    +and CONFIG_DEBUG_SHIRQ may give you more help.


    3.Features
    --
    1.7.1


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