hollalinux
/
linux-sg2042
mirror of https://github.com/sophgo/linux-riscv.git
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

[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>
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
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

21
drivers/pci/pci-sysfs.c
View File

@ -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,
};