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Merge branch 'pci/msi' 

- Document sysfs "irq" attribute, which contains either the INTx IRQ (the
  intended behavior) or the first MSI IRQ (historical mistake retained for
  backwards compatibility) (Barry Song)

- Rework "irq" sysfs show function to explicitly fetch first MSI IRQ
  instead of depending on core to put it in dev->irq, to enable future core
  cleanup (Barry Song)

* pci/msi:
  PCI/sysfs: Explicitly show first MSI IRQ for 'irq'
  PCI: Document /sys/bus/pci/devices/.../irq
This commit is contained in:
Bjorn Helgaas 2021-11-05 11:28:44 -05:00
parent 4917f7189b ac8e3cef58
commit efe6856390
2 changed files with 34 additions and 1 deletions
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11
Documentation/ABI/testing/sysfs-bus-pci
View File

@ -96,6 +96,17 @@ Description:
This attribute indicates the mode that the irq vector named by
the file is in (msi vs. msix)
What: /sys/bus/pci/devices/.../irq
Date: August 2021
Contact: Linux PCI developers <linux-pci@vger.kernel.org>
Description:
If a driver has enabled MSI (not MSI-X), "irq" contains the
IRQ of the first MSI vector. Otherwise "irq" contains the
IRQ of the legacy INTx interrupt.
"irq" being set to 0 indicates that the device isn't
capable of generating legacy INTx interrupts.
What: /sys/bus/pci/devices/.../remove
Date: January 2009
Contact: Linux PCI developers <linux-pci@vger.kernel.org>

24
drivers/pci/pci-sysfs.c
View File

@ -26,6 +26,7 @@
#include <linux/slab.h>
#include <linux/vgaarb.h>
#include <linux/pm_runtime.h>
#include <linux/msi.h>
#include <linux/of.h>
#include "pci.h"
@ -49,7 +50,28 @@ pci_config_attr(subsystem_vendor, "0x%04x\n");
pci_config_attr(subsystem_device, "0x%04x\n");
pci_config_attr(revision, "0x%02x\n");
pci_config_attr(class, "0x%06x\n");
pci_config_attr(irq, "%u\n");
static ssize_t irq_show(struct device *dev,
struct device_attribute *attr,
char *buf)
{
struct pci_dev *pdev = to_pci_dev(dev);
#ifdef CONFIG_PCI_MSI
/*
* For MSI, show the first MSI IRQ; for all other cases including
* MSI-X, show the legacy INTx IRQ.
*/
if (pdev->msi_enabled) {
struct msi_desc *desc = first_pci_msi_entry(pdev);
return sysfs_emit(buf, "%u\n", desc->irq);
}
#endif
return sysfs_emit(buf, "%u\n", pdev->irq);
}
static DEVICE_ATTR_RO(irq);
static ssize_t broken_parity_status_show(struct device *dev,
struct device_attribute *attr,