[+cc Rafael] On Thu, Sep 12, 2024 at 11:00:43AM +0800, Kai-Heng Feng wrote: > On Thu, Sep 12, 2024 at 3:05 AM Bjorn Helgaas <helgaas@xxxxxxxxxx> wrote: > > On Fri, Jul 12, 2024 at 02:24:11PM +0800, Kai-Heng Feng wrote: > > > Some laptops wake up after poweroff when HP Thunderbolt Dock G4 is > > > connected. > > > > > > The following error message can be found during shutdown: > > > pcieport 0000:00:1d.0: AER: Correctable error message received from 0000:09:04.0 > > > pcieport 0000:09:04.0: PCIe Bus Error: severity=Correctable, type=Data Link Layer, (Receiver ID) > > > pcieport 0000:09:04.0: device [8086:0b26] error status/mask=00000080/00002000 > > > pcieport 0000:09:04.0: [ 7] BadDLLP > > > > > > Calling aer_remove() during shutdown can quiesce the error message, > > > however the spurious wakeup still happens. > > > > > > The issue won't happen if the device is in D3 before system shutdown, so > > > putting device to low power state before shutdown to solve the issue. > > > > > > I don't have a sniffer so this is purely guesswork, however I believe > > > putting device to low power state it's the right thing to do. > > > > My objection here is that we don't have an explanation of why this > > should matter or a pointer to any spec language about this situation, > > so it feels a little bit random. > > I have the same feeling too. The PCIe spec doesn't specify what's the > correct power state for shutdown. > So we can only "logically" think the software should put devices to > low power state during shutdown. > > > I suppose the problem wouldn't happen if AER interrupts were disabled? > > We already do disable them in aer_suspend(), but maybe that's not used > > in the shutdown path? > > That was my first thought, so I modified pcie_port_shutdown_service() > to disable AER interrupt. > That approach didn't work though. > > > My understanding is that .shutdown() should turn off device interrupts > > and stop DMA. So maybe we need an aer_shutdown() that disables > > interrupts? > > Logically we should do that. However that approach doesn't solve this issue. I'm not completely clear on the semantics of the .shutdown() interface. The doc at https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/include/linux/device/driver.h?id=v6.10#n73 says "@shutdown: Called at shut-down time to quiesce the device" Turning off device interrupts and DMA *would* fit within the idea of quiescing the device. Does that also include changing the device power state? I dunno. The power state isn't *mentioned* in the .shutdown() context, while it *is* mentioned for .suspend(). IIUC, this patch and commit log uses "shutdown" to refer to a system-wide *poweroff*, which is a different concept despite using the same "shutdown" name. So should the system poweroff procedure use .suspend()? Should it use both .shutdown() and .suspend()? I think it only uses .shutdown() today: kernel_power_off kernel_shutdown_prepare(SYSTEM_POWER_OFF) device_shutdown while (!list_empty(&devices_kset->list)) dev->bus->shutdown(dev) pci_device_shutdown There are several driver .shutdown() methods that do things like this: e1000_shutdown if (system_state == SYSTEM_POWER_OFF) pci_set_power_state(pdev, PCI_D3hot) Maybe that's the right thing and should be done by the PCI core, which is similar to what you propose here. But I think it muddies the definition of .shutdown() a bit by mixing in power management stuff. > > > Link: https://bugzilla.kernel.org/show_bug.cgi?id=219036 > > > Signed-off-by: Kai-Heng Feng <kai.heng.feng@xxxxxxxxxxxxx> > > > --- > > > drivers/pci/pci-driver.c | 8 ++++++++ > > > 1 file changed, 8 insertions(+) > > > > > > diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c > > > index af2996d0d17f..4c6f66f3eb54 100644 > > > --- a/drivers/pci/pci-driver.c > > > +++ b/drivers/pci/pci-driver.c > > > @@ -510,6 +510,14 @@ static void pci_device_shutdown(struct device *dev) > > > if (drv && drv->shutdown) > > > drv->shutdown(pci_dev); > > > > > > + /* > > > + * If driver already changed device's power state, it can mean the > > > + * wakeup setting is in place, or a workaround is used. Hence keep it > > > + * as is. > > > + */ > > > + if (!kexec_in_progress && pci_dev->current_state == PCI_D0) > > > + pci_prepare_to_sleep(pci_dev); > > > + > > > /* > > > * If this is a kexec reboot, turn off Bus Master bit on the > > > * device to tell it to not continue to do DMA. Don't touch > > > -- > > > 2.43.0 > > >
