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[PATCH] PCI: Add a "enable" sysfs attribute to the pci devices to allow userspace (Xorg) to enable devices without doing foul direct access

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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>
This commit is contained in:
Arjan van de Ven 2006-04-29 10:59:08 +02:00 committed by Greg Kroah-Hartman
parent 75acfecaa0
commit 9f125d3048
1 changed files with 21 additions and 0 deletions
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21
drivers/pci/pci-sysfs.c
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@ -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,
};