[PATCH] PCI: Add a "enable" sysfs attribute to the pci devices to allow... (9f125d30) · Commits · 戴 / test

[PATCH] PCI: Add a "enable" sysfs attribute to the pci devices to allow userspace (Xorg) to enable devices without doing foul direct access This patch adds an "enable" sysfs attribute to each PCI device. When read it shows the "enabled-ness" of the device, but you can write a "0" into it to disable a device, and a "1" to enable it. This later is needed for X and other cases where userspace wants to enable the BARs on a device (typical example: to run the video bios on a secundary head). Right now X does all this "by hand" via bitbanging, that's just evil. This allows X to no longer do that but to just let the kernel do this. Signed-off-by:

Arjan van de Ven <arjan@linux.intel.com> CC: Peter Jones <pjones@redhat.com> Acked-by:

Dave Airlie <airlied@linux.ie> Signed-off-by:

Greg Kroah-Hartman <gregkh@suse.de>

drivers/pci/pci-sysfs.c

+21 −0

Original line number	Diff line number	Diff line
		@@ -43,6 +43,7 @@ pci_config_attr(subsystem_vendor, "0x%04x\n");
		pci_config_attr(subsystem_device, "0x%04x\n");
		pci_config_attr(class, "0x%06x\n");
		pci_config_attr(irq, "%u\n");
		pci_config_attr(is_enabled, "%u\n");

		static ssize_t local_cpus_show(struct device *dev,
		struct device_attribute attr, char buf)
		@@ -90,6 +91,25 @@ static ssize_t modalias_show(struct device dev, struct device_attribute attr,
		(u8)(pci_dev->class >> 16), (u8)(pci_dev->class >> 8),
		(u8)(pci_dev->class));
		}
		static ssize_t
		is_enabled_store(struct device dev, struct device_attribute attr,
		const char *buf, size_t count)
		{
		struct pci_dev *pdev = to_pci_dev(dev);

		/* this can crash the machine when done on the "wrong" device */
		if (!capable(CAP_SYS_ADMIN))
		return count;

		if (*buf == '0')
		pci_disable_device(pdev);

		if (*buf == '1')
		pci_enable_device(pdev);

		return count;
		}


		struct device_attribute pci_dev_attrs[] = {
		__ATTR_RO(resource),
		@@ -101,6 +121,7 @@ struct device_attribute pci_dev_attrs[] = {
		__ATTR_RO(irq),
		__ATTR_RO(local_cpus),
		__ATTR_RO(modalias),
		__ATTR(enable, 0600, is_enabled_show, is_enabled_store),
		__ATTR_NULL,
		};

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