From 2f9d7389b5e243abd0c42995a703c4f7cf535af4 Mon Sep 17 00:00:00 2001 From: Valentin Rothberg Date: Fri, 27 Feb 2015 12:55:16 +0100 Subject: MSI-HOWTO.txt: remove reference on IRQF_DISABLED The IRQF_DISABLED is a NOOP and scheduled to be removed. According to Ingo Molnar in commit e58aa3d2d0cc01ad8d6f7f640a0670433f794922 (genirq: Run irq handlers with interrupts disabled), running IRQ handlers with interrupts enabled can cause stack overflows when the interrupt line of the issuing device is still active. This patch removes IRQF_DISABLED from this documentation. It was mentioned to be a solution to avoid deadlocks when a device uses multiple interrupts. As the flag is a NOOP this solution does not work anymore. Signed-off-by: Valentin Rothberg Signed-off-by: Jonathan Corbet --- Documentation/PCI/MSI-HOWTO.txt | 15 +++------------ 1 file changed, 3 insertions(+), 12 deletions(-) (limited to 'Documentation/PCI') diff --git a/Documentation/PCI/MSI-HOWTO.txt b/Documentation/PCI/MSI-HOWTO.txt index 0d920d5..63def8ef 100644 --- a/Documentation/PCI/MSI-HOWTO.txt +++ b/Documentation/PCI/MSI-HOWTO.txt @@ -501,18 +501,9 @@ 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. +acquire the spinlock. Such deadlocks can be avoided by using +spin_lock_irqsave() or spin_lock_irq() which disable local interrupts +and acquire the lock (see Documentation/DocBook/kernel-locking). 4.6 How to tell whether MSI/MSI-X is enabled on a device -- cgit v1.1 From 654d2e7cd18b8acc4e2accdcc0c1eadb8d786722 Mon Sep 17 00:00:00 2001 From: Masanari Iida Date: Thu, 19 Mar 2015 00:29:30 +0900 Subject: doc:pci: Fix typo in Documentation/PCI This patch fix spelling typo in Documentation/PCI. Signed-off-by: Masanari Iida Signed-off-by: Jonathan Corbet --- Documentation/PCI/MSI-HOWTO.txt | 6 +++--- Documentation/PCI/pci-error-recovery.txt | 2 +- Documentation/PCI/pcieaer-howto.txt | 4 ++-- 3 files changed, 6 insertions(+), 6 deletions(-) (limited to 'Documentation/PCI') diff --git a/Documentation/PCI/MSI-HOWTO.txt b/Documentation/PCI/MSI-HOWTO.txt index 63def8ef..1179850 100644 --- a/Documentation/PCI/MSI-HOWTO.txt +++ b/Documentation/PCI/MSI-HOWTO.txt @@ -353,7 +353,7 @@ retry: rc = pci_enable_msix_range(adapter->pdev, adapter->msix_entries, maxvec, maxvec); /* - * -ENOSPC is the only error code allowed to be analized + * -ENOSPC is the only error code allowed to be analyzed */ if (rc == -ENOSPC) { if (maxvec == 1) @@ -370,7 +370,7 @@ retry: return rc; } -Note how pci_enable_msix_range() return value is analized for a fallback - +Note how pci_enable_msix_range() return value is analyzed for a fallback - any error code other than -ENOSPC indicates a fatal error and should not be retried. @@ -486,7 +486,7 @@ during development. If your device supports both MSI-X and MSI capabilities, you should use the MSI-X facilities in preference to the MSI facilities. As mentioned above, MSI-X supports any number of interrupts between 1 and 2048. -In constrast, MSI is restricted to a maximum of 32 interrupts (and +In contrast, MSI is restricted to a maximum of 32 interrupts (and must be a power of two). In addition, the MSI interrupt vectors must be allocated consecutively, so the system might not be able to allocate as many vectors for MSI as it could for MSI-X. On some platforms, MSI diff --git a/Documentation/PCI/pci-error-recovery.txt b/Documentation/PCI/pci-error-recovery.txt index 898ded2..ac26869 100644 --- a/Documentation/PCI/pci-error-recovery.txt +++ b/Documentation/PCI/pci-error-recovery.txt @@ -256,7 +256,7 @@ STEP 4: Slot Reset ------------------ In response to a return value of PCI_ERS_RESULT_NEED_RESET, the -the platform will peform a slot reset on the requesting PCI device(s). +the platform will perform a slot reset on the requesting PCI device(s). The actual steps taken by a platform to perform a slot reset will be platform-dependent. Upon completion of slot reset, the platform will call the device slot_reset() callback. diff --git a/Documentation/PCI/pcieaer-howto.txt b/Documentation/PCI/pcieaer-howto.txt index 26d3d94..b4987c0 100644 --- a/Documentation/PCI/pcieaer-howto.txt +++ b/Documentation/PCI/pcieaer-howto.txt @@ -66,8 +66,8 @@ hardware (mostly chipsets) has root ports that cannot obtain the reporting source ID. nosourceid=n by default. 2.3 AER error output -When a PCI-E AER error is captured, an error message will be outputed to -console. If it's a correctable error, it is outputed as a warning. +When a PCI-E AER error is captured, an error message will be outputted to +console. If it's a correctable error, it is outputted as a warning. Otherwise, it is printed as an error. So users could choose different log level to filter out correctable error messages. -- cgit v1.1