On Fri, 11 Jan 2008 11:02:29 -0800 Greg KH <[EMAIL PROTECTED]> wrote:
> On Tue, Dec 25, 2007 at 03:26:05AM -0800, Arjan van de Ven wrote: > > > > This patch also adds a sysfs property for each device into which > > root can write a '1' to enable extended configuration space. The > > kernel will print a notice into dmesg when this happens (including > > the name of the app) so that if the system crashes as a result of > > this action, the user can know what action/tool caused it. > > Can you send me a follow-on patch that documents this in > Documentation/ABI please. > --- Documentation/ABI/testing/sysfs-pci-extended-config | 39 ++++++++++++++++++++ 1 file changed, 39 insertions(+) Index: linux-2.6.24-rc7/Documentation/ABI/testing/sysfs-pci-extended-config =================================================================== --- /dev/null +++ linux-2.6.24-rc7/Documentation/ABI/testing/sysfs-pci-extended-config @@ -0,0 +1,39 @@ +What: /sys/devices/pci<bus>/<device>/extended_config_space +Date: January 11, 2008 +Contact: Arjan van de Ven <[EMAIL PROTECTED]> +Description: + This attribute is for use for system-diagnostic software + only. + + The kernel may decide to restrict PCI configuration space + access for userspace to the first 64 or 256 bytes by + default, for stability reasons. This attribute, when + present, can be used to request access to the full + 4Kb from the kernel. + + Request to get access to the full 4Kb can be done by + writing a '1' into this attribute file. All other values + are reserved for future use and should not be used by + software at this point. + + The kernel may log the request to the various kernel + logging services. The kernel may decide to ignore the + request if the kernel deems extended configuration space + access not reliable enough for the system or the device. + The kernel may decide to not present this attribute + if the kernel decides extended config space is reliable + and made available by default, or if the kernel decides + that extended configuration space will never be + accessible. + + Software needs to gracefully deal with getting the + access not granted. Software also needs to gracefully deal + with this attribute not being present. + + Due to the fragility of extended configuratio space, + system diagnostic software should only set this attribute + on explicit user request, or in the case of GUI like tools, + at least with explicit user permission. + + + -- If you want to reach me at my work email, use [EMAIL PROTECTED] For development, discussion and tips for power savings, visit http://www.lesswatts.org -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
