On Tue, 31 Jul 2012, Huang Ying wrote: > > What happens when you run lspci and the device is in D3cold? Then even > > if the parent bridge is active, lspci will still fail. > > > > It seems that in this case you need to resume the device itself, not > > just its parent. > > How about the following patch? > > Subject: [BUGFIX] PCI/PM: Keep parent bridge active when read/write config reg > > This patch fixes the following bug: > > http://marc.info/?l=linux-pci&m=134338059022620&w=2 > > Where lspci does not work properly if a device and the corresponding > parent bridge (such as PCIe port) is suspended. This is because the > device configuration space registers will be not accessible if the > corresponding parent bridge is suspended or the device is put into > D3cold state. > > To solve the issue, the bridge/PCIe port connected to the device is > put into active state before read/write configuration space registers. > If the device is in D3cold state, it will be put into active state > too. > > To avoid resume/suspend PCIe port for each configuration register > read/write, a small delay is added before the PCIe port to go > suspended. The patch looks reasonable to me, but I haven't tested it. Alan Stern -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
