From arjan@linux.intel.com Sat Apr 29 01:59:16 2006 From: Arjan van de Ven Subject: PCI: Add a "enable" sysfs attribute to the pci devices to allow userspace (Xorg) to enable devices without doing foul direct access To: Andrew Morton Cc: greg@kroah.com, airlied@linux.ie, pjones@redhat.com Date: Sat, 29 Apr 2006 10:59:08 +0200 Message-Id: <1146301148.3125.7.camel@laptopd505.fenrus.org> 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 CC: Peter Jones Acked-by: Dave Airlie Signed-off-by: Greg Kroah-Hartman --- drivers/pci/pci-sysfs.c | 21 +++++++++++++++++++++ 1 file changed, 21 insertions(+) --- gregkh-2.6.orig/drivers/pci/pci-sysfs.c +++ gregkh-2.6/drivers/pci/pci-sysfs.c @@ -43,6 +43,7 @@ pci_config_attr(subsystem_vendor, "0x%04 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 devi (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, };