[lkml]   [2011]   [Oct]   [22]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
Patch in this message
Subject[PATCH 47/49] Documentation: irq: Change documents related to IRQF_DISABLED
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 <>
Cc: Bjorn Helgaas <>
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
+do so, you should find out what's the mismatch between the shared IRQs,
+and CONFIG_DEBUG_SHIRQ may give you more help.


 \ /
  Last update: 2011-10-22 12:21    [W:0.147 / U:9.764 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site