Re: [PATCH v5 0/5] Verify devices transition from D3cold to D0

[Bjorn Helgaas <helgaas@kernel.org>]

On Wed, Dec 04, 2024 at 11:30:51AM -0600, Mario Limonciello wrote:
> On 8/23/2024 10:40, Mario Limonciello wrote:
> > From: Mario Limonciello <mario.limonciello@amd.com>
> > 
> > Gary has reported that when a dock is plugged into a system at the same
> > time the autosuspend delay has tripped that the USB4 stack malfunctions.
> > 
> > Messages show up like this:
> > 
> > ```
> > thunderbolt 0000:e5:00.6: ring_interrupt_active: interrupt for TX ring 0 is already enabled
> > ```
> > 
> > Furthermore the USB4 router is non-functional at this point.
> > 
> > Those messages happen because the device is still in D3cold at the time
> > that the PCI core handed control back to the USB4 connection manager
> > (thunderbolt).
> > 
> > The issue is that it takes time for a device to enter D3cold and do a
> > conventional reset, and then more time for it to exit D3cold.
> > 
> > This appears not to be a new problem; previously there were very similar
> > reports from Ryzen XHCI controllers.  Quirks were added for those.
> > Furthermore; adding extra logging it's apparent that other PCI devices
> > in the system can take more than 10ms to recover from D3cold as well.
> > 
> > This series add a wait into pci_power_up() specifically for D3cold exit and
> > then drops the quirks that were previously used for the Ryzen XHCI controllers.
> > 
> > Mario Limonciello (5):
> >    PCI: Use an enum for reset type in pci_dev_wait()
> >    PCI: Check PCI_PM_CTRL instead of PCI_COMMAND in pci_dev_wait()
> >    PCI: Verify functions currently in D3cold have entered D0
> >    PCI: Allow Ryzen XHCI controllers into D3cold and drop delays
> >    PCI: Drop Radeon quirk for Macbook Pro 8.2
> > 
> >   drivers/pci/pci-driver.c    |  2 +-
> >   drivers/pci/pci.c           | 70 +++++++++++++++++++++++++++----------
> >   drivers/pci/pci.h           | 13 ++++++-
> >   drivers/pci/pcie/dpc.c      |  2 +-
> >   drivers/pci/quirks.c        | 25 -------------
> >   drivers/usb/host/xhci-pci.c | 11 ------
> >   6 files changed, 66 insertions(+), 57 deletions(-)
> 
> Bjorn,
> 
> This series has stalled a while.
> 
> Mika and I went back and forth and I think are generally in agreement so I
> think it's waiting on your feedback.
> 
> Can you take another look?
> 
> The alternative is to add some more piles of quirks, but I'm hoping that we
> can go this direction and drop a bunch of the old ones instead.
> 
> LMK if you want me to rebase it on 6.13-rc1 and resend a v6.

I'm still stuck on patch 2/5 because I'm not aware of any spec
language about polling PCI_PM_CTRL to wait for a power state
transition, so it seems really ad hoc.

If you do rebase to v6.13-rc1, in the 2/5 commit log,
s/evices/devices/.

I guess that whole patch and commit log needs updating since the RRS
code was added to pci_dev_wait() in the interim, so the "device that
has gone through a reset may return a value in PCI_COMMAND but that
doesn't mean it's finished transitioning to D0" doesn't directly apply
anymore.

Bjorn