On Monday, 6 August 2007 17:50, Joonwoo Park wrote: > 2007/8/6, Rafael J. Wysocki <[EMAIL PROTECTED]>: > > On Monday, 6 August 2007 15:42, Joonwoo Park wrote: > > > Hi. > > > I think that the pci_set_power_state() has bug. > > > The specification says that some delays is required. > > > > And they are in place, AFAICS (from drivers/pci/pci.c): > > > > /* Mandatory power management transition delays */ > > /* see PCI PM 1.1 5.6.1 table 18 */ > > if (state == PCI_D3hot || dev->current_state == PCI_D3hot) > > msleep(pci_pm_d3_delay); > > else if (state == PCI_D2 || dev->current_state == PCI_D2) > > udelay(200); > > > > The problem is occurred when state is 'PCI_D0', so those codes can't cover it. > But pci pm specification 5.4.1 says that when programmed to D0 the > equivalent of a warm reset, delay for the duration of the D3hot to D0 > Uninitialized state > transition (10ms) to pci signal drivers remain disabled is required.
Section 5.4.1 of PCI PM 1.1. spec is about D3_hot. Specifically, it says that if a device in D3_hot is programmed to D0, it performs the equivalent of a warm reset. IOW, this is supposed to happen if the current state is D3_hot and the targed state is D0, which is covered by the code snippet above. Greetings, Rafael -- "Premature optimization is the root of all evil." - Donald Knuth - 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/
