On Wed, Nov 28, 2012 at 3:43 PM, Rafael J. Wysocki <rjw@xxxxxxx> wrote: > On Wednesday, November 28, 2012 03:25:59 PM Bjorn Helgaas wrote: >> On Tue, Nov 20, 2012 at 1:08 AM, Huang Ying <ying.huang@xxxxxxxxx> wrote: >> > For unbound PCI devices, what we need is: >> > >> > - Always in D0 state, because some devices does not work again after >> > being put into D3 by the PCI bus. >> > >> > - In SUSPENDED state if allowed, so that the parent devices can still >> > be put into low power state. >> > >> > To satisfy these requirement, the runtime PM for the unbound PCI >> > devices are disabled and set to SUSPENDED state. One issue of this >> > solution is that the PCI devices will be put into SUSPENDED state even >> > if the SUSPENDED state is forbidden via the sysfs interface >> > (.../power/control) of the device. This is not an issue for most >> > devices, because most PCI devices are not used at all if unbounded. >> > But there are exceptions. For example, unbound VGA card can be used >> > for display, but suspend its parents make it stop working. >> > >> > To fix the issue, we keep the runtime PM enabled when the PCI devices >> > are unbound. But the runtime PM callbacks will do nothing if the PCI >> > devices are unbound. This way, we can put the PCI devices into >> > SUSPENDED state without put the PCI devices into D3 state. >> >> Does this fix a reported problem? Is there a bug report URL? What >> problem would a user notice? > > There is a BZ: https://bugzilla.kernel.org/show_bug.cgi?id=48201 I added the BZ link and put this in my -next branch. Thanks! Bjorn -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
